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gerrit-public.fairphone.software / toolchain / llvm-project / de7ab801cce0a4e60b75f5cd9738f3f7e722db08 / . / llvm / docs / LangRef.html
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5 <title>LLVM Assembly Language Reference Manual</title>
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7 <meta name="author" content="Chris Lattner">
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]8 <meta name="description"
Reid Spencercb84e432004-08-26 20:44:00 +0000[diff] [blame]9 content="LLVM Assembly Language Reference Manual.">
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11</head>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]14
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]15<h1>LLVM Language Reference Manual</h1>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendling8693ef82009-07-20 02:41:50 +0000[diff] [blame]25 <li><a href="#linkage_private">'<tt>private</tt>' Linkage</a></li>
26 <li><a href="#linkage_linker_private">'<tt>linker_private</tt>' Linkage</a></li>
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]27 <li><a href="#linkage_linker_private_weak">'<tt>linker_private_weak</tt>' Linkage</a></li>
Bill Wendling578ee402010-08-20 22:05:50 +0000[diff] [blame]28 <li><a href="#linkage_linker_private_weak_def_auto">'<tt>linker_private_weak_def_auto</tt>' Linkage</a></li>
Bill Wendling8693ef82009-07-20 02:41:50 +0000[diff] [blame]29 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
30 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
31 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
32 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
33 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
34 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
35 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
Chris Lattner80d73c72009-10-10 18:26:06 +0000[diff] [blame]36 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendling8693ef82009-07-20 02:41:50 +0000[diff] [blame]37 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
38 <li><a href="#linkage_external">'<tt>externally visible</tt>' Linkage</a></li>
39 <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
40 <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]41 </ol>
42 </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]43 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]44 <li><a href="#namedtypes">Named Types</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]45 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]46 <li><a href="#functionstructure">Functions</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]47 <li><a href="#aliasstructure">Aliases</a></li>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]48 <li><a href="#namedmetadatastructure">Named Metadata</a></li>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]49 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]50 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]51 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]52 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]53 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]54 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]55 <li><a href="#volatile">Volatile Memory Accesses</a></li>
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]56 <li><a href="#memmodel">Memory Model for Concurrent Operations</a></li>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]57 <li><a href="#ordering">Atomic Memory Ordering Constraints</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]58 </ol>
59 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]60 <li><a href="#typesystem">Type System</a>
61 <ol>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]62 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]63 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]64 <ol>
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]65 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]66 <li><a href="#t_floating">Floating Point Types</a></li>
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]67 <li><a href="#t_x86mmx">X86mmx Type</a></li>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]68 <li><a href="#t_void">Void Type</a></li>
69 <li><a href="#t_label">Label Type</a></li>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]70 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]71 </ol>
72 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]73 <li><a href="#t_derived">Derived Types</a>
74 <ol>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]75 <li><a href="#t_aggregate">Aggregate Types</a>
76 <ol>
77 <li><a href="#t_array">Array Type</a></li>
78 <li><a href="#t_struct">Structure Type</a></li>
Chris Lattner2a843822011-07-23 19:59:08 +0000[diff] [blame]79 <li><a href="#t_opaque">Opaque Structure Types</a></li>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]80 <li><a href="#t_vector">Vector Type</a></li>
81 </ol>
82 </li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]83 <li><a href="#t_function">Function Type</a></li>
84 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]85 </ol>
86 </li>
87 </ol>
88 </li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]89 <li><a href="#constants">Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]90 <ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]91 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]92 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]93 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
94 <li><a href="#undefvalues">Undefined Values</a></li>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]95 <li><a href="#trapvalues">Trap Values</a></li>
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]96 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]97 <li><a href="#constantexprs">Constant Expressions</a></li>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]98 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]99 </li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]100 <li><a href="#othervalues">Other Values</a>
101 <ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]102 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]103 <li><a href="#metadata">Metadata Nodes and Metadata Strings</a></li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]104 </ol>
105 </li>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]106 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
107 <ol>
108 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]109 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
110 Global Variable</a></li>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]111 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
112 Global Variable</a></li>
113 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
114 Global Variable</a></li>
115 </ol>
116 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]117 <li><a href="#instref">Instruction Reference</a>
118 <ol>
119 <li><a href="#terminators">Terminator Instructions</a>
120 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]121 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
122 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]123 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]124 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]125 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]126 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]127 <li><a href="#i_resume">'<tt>resume</tt>' Instruction</a></li>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]128 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]129 </ol>
130 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]131 <li><a href="#binaryops">Binary Operations</a>
132 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]133 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]134 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]135 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]136 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]137 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]138 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]139 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
140 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
141 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]142 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
143 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
144 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]145 </ol>
146 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]147 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
148 <ol>
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]149 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
150 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
151 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]152 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]153 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]154 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]155 </ol>
156 </li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]157 <li><a href="#vectorops">Vector Operations</a>
158 <ol>
159 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
160 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
161 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]162 </ol>
163 </li>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]164 <li><a href="#aggregateops">Aggregate Operations</a>
165 <ol>
166 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
167 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
168 </ol>
169 </li>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]170 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]171 <ol>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]172 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
173 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
174 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
175 <li><a href="#i_fence">'<tt>fence</tt>' Instruction</a></li>
176 <li><a href="#i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a></li>
177 <li><a href="#i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a></li>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]178 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]179 </ol>
180 </li>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]181 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]182 <ol>
183 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
184 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
185 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
186 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
187 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]188 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
189 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
190 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
191 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]192 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
193 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]194 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]195 </ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]196 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]197 <li><a href="#otherops">Other Operations</a>
198 <ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]199 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
200 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]201 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]202 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]203 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]204 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]205 <li><a href="#i_landingpad">'<tt>landingpad</tt>' Instruction</a></li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]206 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]207 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]208 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]209 </li>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]210 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]211 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]212 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
213 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]214 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
215 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
216 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]217 </ol>
218 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]219 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
220 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]221 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
222 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
223 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]224 </ol>
225 </li>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]226 <li><a href="#int_codegen">Code Generator Intrinsics</a>
227 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]228 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
229 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
230 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
231 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
232 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
233 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Dan Gohmane58f7b32010-05-26 21:56:15 +0000[diff] [blame]234 <li><a href="#int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]235 </ol>
236 </li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]237 <li><a href="#int_libc">Standard C Library Intrinsics</a>
238 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]239 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
240 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
241 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
242 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
243 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]244 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
245 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
246 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohmane635c522011-05-27 00:36:31 +0000[diff] [blame]247 <li><a href="#int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a></li>
248 <li><a href="#int_log">'<tt>llvm.log.*</tt>' Intrinsic</a></li>
Cameron Zwarichf03fa182011-07-08 21:39:21 +0000[diff] [blame]249 <li><a href="#int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a></li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]250 </ol>
251 </li>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]252 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]253 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]254 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]255 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
256 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
257 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]258 </ol>
259 </li>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]260 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
261 <ol>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]262 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
263 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
264 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
265 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
266 <li><a href="#int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]267 <li><a href="#int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]268 </ol>
269 </li>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]270 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
271 <ol>
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]272 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
273 <li><a href="#int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a></li>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]274 </ol>
275 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]276 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]277 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]278 <li><a href="#int_trampoline">Trampoline Intrinsics</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]279 <ol>
280 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]281 <li><a href="#int_at">'<tt>llvm.adjust.trampoline</tt>' Intrinsic</a></li>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]282 </ol>
283 </li>
Bill Wendlingf85850f2008-11-18 22:10:53 +0000[diff] [blame]284 <li><a href="#int_atomics">Atomic intrinsics</a>
285 <ol>
286 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
287 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
288 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
289 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
290 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
291 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
292 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
293 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
294 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
295 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
296 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
297 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
298 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
299 </ol>
300 </li>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]301 <li><a href="#int_memorymarkers">Memory Use Markers</a>
302 <ol>
303 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
304 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
305 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
306 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
307 </ol>
308 </li>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]309 <li><a href="#int_general">General intrinsics</a>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]310 <ol>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]311 <li><a href="#int_var_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]312 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]313 <li><a href="#int_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]314 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]315 <li><a href="#int_trap">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]316 '<tt>llvm.trap</tt>' Intrinsic</a></li>
317 <li><a href="#int_stackprotector">
318 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]319 <li><a href="#int_objectsize">
320 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]321 </ol>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]322 </li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]323 </ol>
324 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]325</ol>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]326
327<div class="doc_author">
328 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
329 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]330</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]331
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]332<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]333<h2><a name="abstract">Abstract</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]334<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]335
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]336<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]337
338<p>This document is a reference manual for the LLVM assembly language. LLVM is
339 a Static Single Assignment (SSA) based representation that provides type
340 safety, low-level operations, flexibility, and the capability of representing
341 'all' high-level languages cleanly. It is the common code representation
342 used throughout all phases of the LLVM compilation strategy.</p>
343
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]344</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]345
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]346<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]347<h2><a name="introduction">Introduction</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]348<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]349
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]350<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]351
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]352<p>The LLVM code representation is designed to be used in three different forms:
353 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
354 for fast loading by a Just-In-Time compiler), and as a human readable
355 assembly language representation. This allows LLVM to provide a powerful
356 intermediate representation for efficient compiler transformations and
357 analysis, while providing a natural means to debug and visualize the
358 transformations. The three different forms of LLVM are all equivalent. This
359 document describes the human readable representation and notation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]360
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]361<p>The LLVM representation aims to be light-weight and low-level while being
362 expressive, typed, and extensible at the same time. It aims to be a
363 "universal IR" of sorts, by being at a low enough level that high-level ideas
364 may be cleanly mapped to it (similar to how microprocessors are "universal
365 IR's", allowing many source languages to be mapped to them). By providing
366 type information, LLVM can be used as the target of optimizations: for
367 example, through pointer analysis, it can be proven that a C automatic
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]368 variable is never accessed outside of the current function, allowing it to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]369 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]370
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]371<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]372<h4>
373 <a name="wellformed">Well-Formedness</a>
374</h4>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]375
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]376<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]377
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]378<p>It is important to note that this document describes 'well formed' LLVM
379 assembly language. There is a difference between what the parser accepts and
380 what is considered 'well formed'. For example, the following instruction is
381 syntactically okay, but not well formed:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]382
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]383<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]384%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]385</pre>
386
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]387<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
388 LLVM infrastructure provides a verification pass that may be used to verify
389 that an LLVM module is well formed. This pass is automatically run by the
390 parser after parsing input assembly and by the optimizer before it outputs
391 bitcode. The violations pointed out by the verifier pass indicate bugs in
392 transformation passes or input to the parser.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]393
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]394</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]395
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]396</div>
397
Chris Lattner87a3dbe2007-10-03 17:34:29 +0000[diff] [blame]398<!-- Describe the typesetting conventions here. -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]399
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]400<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]401<h2><a name="identifiers">Identifiers</a></h2>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]402<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]403
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]404<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]405
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]406<p>LLVM identifiers come in two basic types: global and local. Global
407 identifiers (functions, global variables) begin with the <tt>'@'</tt>
408 character. Local identifiers (register names, types) begin with
409 the <tt>'%'</tt> character. Additionally, there are three different formats
410 for identifiers, for different purposes:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]411
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]412<ol>
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]413 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]414 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
415 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
416 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
417 other characters in their names can be surrounded with quotes. Special
418 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
419 ASCII code for the character in hexadecimal. In this way, any character
420 can be used in a name value, even quotes themselves.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]421
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]422 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]423 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]424
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]425 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]426 constants</a>, below.</li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]427</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]428
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]429<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]430 don't need to worry about name clashes with reserved words, and the set of
431 reserved words may be expanded in the future without penalty. Additionally,
432 unnamed identifiers allow a compiler to quickly come up with a temporary
433 variable without having to avoid symbol table conflicts.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]434
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]435<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]436 languages. There are keywords for different opcodes
437 ('<tt><a href="#i_add">add</a></tt>',
438 '<tt><a href="#i_bitcast">bitcast</a></tt>',
439 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
440 ('<tt><a href="#t_void">void</a></tt>',
441 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
442 reserved words cannot conflict with variable names, because none of them
443 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]444
445<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]446 '<tt>%X</tt>' by 8:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]447
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]448<p>The easy way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]449
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]450<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]451%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]452</pre>
453
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]454<p>After strength reduction:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]455
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]456<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]457%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]458</pre>
459
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]460<p>And the hard way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]461
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]462<pre class="doc_code">
Gabor Greifbd0328f2009-10-28 13:05:07 +0000[diff] [blame]463%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
464%1 = <a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]465%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]466</pre>
467
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]468<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
469 lexical features of LLVM:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]470
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]471<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]472 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]473 line.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]474
475 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]476 assigned to a named value.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]477
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]478 <li>Unnamed temporaries are numbered sequentially</li>
479</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]480
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]481<p>It also shows a convention that we follow in this document. When
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]482 demonstrating instructions, we will follow an instruction with a comment that
483 defines the type and name of value produced. Comments are shown in italic
484 text.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]485
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]486</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]487
488<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]489<h2><a name="highlevel">High Level Structure</a></h2>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]490<!-- *********************************************************************** -->
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]491<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]492<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]493<h3>
494 <a name="modulestructure">Module Structure</a>
495</h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]496
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]497<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]498
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]499<p>LLVM programs are composed of "Module"s, each of which is a translation unit
500 of the input programs. Each module consists of functions, global variables,
501 and symbol table entries. Modules may be combined together with the LLVM
502 linker, which merges function (and global variable) definitions, resolves
503 forward declarations, and merges symbol table entries. Here is an example of
504 the "hello world" module:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]505
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]506<pre class="doc_code">
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]507<i>; Declare the string constant as a global constant.</i>&nbsp;
Nick Lewyckyfea7ddc2011-01-29 01:09:53 +0000[diff] [blame]508<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a>&nbsp;<a href="#globalvars">constant</a>&nbsp;<a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>&nbsp;
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]509
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]510<i>; External declaration of the puts function</i>&nbsp;
511<a href="#functionstructure">declare</a> i32 @puts(i8*) <i>; i32 (i8*)* </i>&nbsp;
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]512
513<i>; Definition of main function</i>
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]514define i32 @main() { <i>; i32()* </i>&nbsp;
515 <i>; Convert [13 x i8]* to i8 *...</i>&nbsp;
516 %cast210 = <a href="#i_getelementptr">getelementptr</a> [13 x i8]* @.LC0, i64 0, i64 0 <i>; i8*</i>&nbsp;
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]517
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]518 <i>; Call puts function to write out the string to stdout.</i>&nbsp;
519 <a href="#i_call">call</a> i32 @puts(i8* %cast210) <i>; i32</i>&nbsp;
520 <a href="#i_ret">ret</a> i32 0&nbsp;
521}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]522
523<i>; Named metadata</i>
524!1 = metadata !{i32 41}
525!foo = !{!1, null}
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]526</pre>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]527
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]528<p>This example is made up of a <a href="#globalvars">global variable</a> named
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]529 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]530 a <a href="#functionstructure">function definition</a> for
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]531 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
532 "<tt>foo"</tt>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]533
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]534<p>In general, a module is made up of a list of global values, where both
535 functions and global variables are global values. Global values are
536 represented by a pointer to a memory location (in this case, a pointer to an
537 array of char, and a pointer to a function), and have one of the
538 following <a href="#linkage">linkage types</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]539
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]540</div>
541
542<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]543<h3>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]544 <a name="linkage">Linkage Types</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]545</h3>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]546
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]547<div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]548
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]549<p>All Global Variables and Functions have one of the following types of
550 linkage:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]551
552<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]553 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]554 <dd>Global values with "<tt>private</tt>" linkage are only directly accessible
555 by objects in the current module. In particular, linking code into a
556 module with an private global value may cause the private to be renamed as
557 necessary to avoid collisions. Because the symbol is private to the
558 module, all references can be updated. This doesn't show up in any symbol
559 table in the object file.</dd>
Rafael Espindola6de96a12009-01-15 20:18:42 +0000[diff] [blame]560
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]561 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]562 <dd>Similar to <tt>private</tt>, but the symbol is passed through the
563 assembler and evaluated by the linker. Unlike normal strong symbols, they
564 are removed by the linker from the final linked image (executable or
565 dynamic library).</dd>
566
567 <dt><tt><b><a name="linkage_linker_private_weak">linker_private_weak</a></b></tt></dt>
568 <dd>Similar to "<tt>linker_private</tt>", but the symbol is weak. Note that
569 <tt>linker_private_weak</tt> symbols are subject to coalescing by the
570 linker. The symbols are removed by the linker from the final linked image
571 (executable or dynamic library).</dd>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]572
Bill Wendling578ee402010-08-20 22:05:50 +0000[diff] [blame]573 <dt><tt><b><a name="linkage_linker_private_weak_def_auto">linker_private_weak_def_auto</a></b></tt></dt>
574 <dd>Similar to "<tt>linker_private_weak</tt>", but it's known that the address
575 of the object is not taken. For instance, functions that had an inline
576 definition, but the compiler decided not to inline it. Note,
577 unlike <tt>linker_private</tt> and <tt>linker_private_weak</tt>,
578 <tt>linker_private_weak_def_auto</tt> may have only <tt>default</tt>
579 visibility. The symbols are removed by the linker from the final linked
580 image (executable or dynamic library).</dd>
581
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]582 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendling36321712010-06-29 22:34:52 +0000[diff] [blame]583 <dd>Similar to private, but the value shows as a local symbol
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]584 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
585 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]586
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]587 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]588 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]589 into the object file corresponding to the LLVM module. They exist to
590 allow inlining and other optimizations to take place given knowledge of
591 the definition of the global, which is known to be somewhere outside the
592 module. Globals with <tt>available_externally</tt> linkage are allowed to
593 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
594 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]595
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]596 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]597 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner0de4caa2010-01-09 19:15:14 +0000[diff] [blame]598 the same name when linkage occurs. This can be used to implement
599 some forms of inline functions, templates, or other code which must be
600 generated in each translation unit that uses it, but where the body may
601 be overridden with a more definitive definition later. Unreferenced
602 <tt>linkonce</tt> globals are allowed to be discarded. Note that
603 <tt>linkonce</tt> linkage does not actually allow the optimizer to
604 inline the body of this function into callers because it doesn't know if
605 this definition of the function is the definitive definition within the
606 program or whether it will be overridden by a stronger definition.
607 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
608 linkage.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]609
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]610 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]611 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
612 <tt>linkonce</tt> linkage, except that unreferenced globals with
613 <tt>weak</tt> linkage may not be discarded. This is used for globals that
614 are declared "weak" in C source code.</dd>
615
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]616 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]617 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
618 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
619 global scope.
620 Symbols with "<tt>common</tt>" linkage are merged in the same way as
621 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]622 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]623 must have a zero initializer, and may not be marked '<a
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]624 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
625 have common linkage.</dd>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]626
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]627
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]628 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]629 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]630 pointer to array type. When two global variables with appending linkage
631 are linked together, the two global arrays are appended together. This is
632 the LLVM, typesafe, equivalent of having the system linker append together
633 "sections" with identical names when .o files are linked.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]634
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]635 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]636 <dd>The semantics of this linkage follow the ELF object file model: the symbol
637 is weak until linked, if not linked, the symbol becomes null instead of
638 being an undefined reference.</dd>
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]639
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]640 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
641 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]642 <dd>Some languages allow differing globals to be merged, such as two functions
643 with different semantics. Other languages, such as <tt>C++</tt>, ensure
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]644 that only equivalent globals are ever merged (the "one definition rule"
645 &mdash; "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]646 and <tt>weak_odr</tt> linkage types to indicate that the global will only
647 be merged with equivalent globals. These linkage types are otherwise the
648 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]649
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]650 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]651 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]652 visible, meaning that it participates in linkage and can be used to
653 resolve external symbol references.</dd>
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]654</dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]655
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]656<p>The next two types of linkage are targeted for Microsoft Windows platform
657 only. They are designed to support importing (exporting) symbols from (to)
658 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]659
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]660<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]661 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]662 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]663 or variable via a global pointer to a pointer that is set up by the DLL
664 exporting the symbol. On Microsoft Windows targets, the pointer name is
665 formed by combining <code>__imp_</code> and the function or variable
666 name.</dd>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]667
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]668 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]669 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]670 pointer to a pointer in a DLL, so that it can be referenced with the
671 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
672 name is formed by combining <code>__imp_</code> and the function or
673 variable name.</dd>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]674</dl>
675
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]676<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
677 another module defined a "<tt>.LC0</tt>" variable and was linked with this
678 one, one of the two would be renamed, preventing a collision. Since
679 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
680 declarations), they are accessible outside of the current module.</p>
681
682<p>It is illegal for a function <i>declaration</i> to have any linkage type
683 other than "externally visible", <tt>dllimport</tt>
684 or <tt>extern_weak</tt>.</p>
685
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]686<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]687 or <tt>weak_odr</tt> linkages.</p>
688
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]689</div>
690
691<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]692<h3>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]693 <a name="callingconv">Calling Conventions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]694</h3>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]695
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]696<div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]697
698<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]699 and <a href="#i_invoke">invokes</a> can all have an optional calling
700 convention specified for the call. The calling convention of any pair of
701 dynamic caller/callee must match, or the behavior of the program is
702 undefined. The following calling conventions are supported by LLVM, and more
703 may be added in the future:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]704
705<dl>
706 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]707 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]708 specified) matches the target C calling conventions. This calling
709 convention supports varargs function calls and tolerates some mismatch in
710 the declared prototype and implemented declaration of the function (as
711 does normal C).</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]712
713 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]714 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]715 (e.g. by passing things in registers). This calling convention allows the
716 target to use whatever tricks it wants to produce fast code for the
717 target, without having to conform to an externally specified ABI
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]718 (Application Binary Interface).
719 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattnera179e4d2010-03-11 00:22:57 +0000[diff] [blame]720 when this or the GHC convention is used.</a> This calling convention
721 does not support varargs and requires the prototype of all callees to
722 exactly match the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]723
724 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]725 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]726 as possible under the assumption that the call is not commonly executed.
727 As such, these calls often preserve all registers so that the call does
728 not break any live ranges in the caller side. This calling convention
729 does not support varargs and requires the prototype of all callees to
730 exactly match the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]731
Chris Lattnera179e4d2010-03-11 00:22:57 +0000[diff] [blame]732 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
733 <dd>This calling convention has been implemented specifically for use by the
734 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
735 It passes everything in registers, going to extremes to achieve this by
736 disabling callee save registers. This calling convention should not be
737 used lightly but only for specific situations such as an alternative to
738 the <em>register pinning</em> performance technique often used when
739 implementing functional programming languages.At the moment only X86
740 supports this convention and it has the following limitations:
741 <ul>
742 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
743 floating point types are supported.</li>
744 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
745 6 floating point parameters.</li>
746 </ul>
747 This calling convention supports
748 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
749 requires both the caller and callee are using it.
750 </dd>
751
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]752 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]753 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]754 target-specific calling conventions to be used. Target specific calling
755 conventions start at 64.</dd>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]756</dl>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]757
758<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]759 support Pascal conventions or any other well-known target-independent
760 convention.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]761
762</div>
763
764<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]765<h3>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]766 <a name="visibility">Visibility Styles</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]767</h3>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]768
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]769<div>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]770
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]771<p>All Global Variables and Functions have one of the following visibility
772 styles:</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]773
774<dl>
775 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]776 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]777 that the declaration is visible to other modules and, in shared libraries,
778 means that the declared entity may be overridden. On Darwin, default
779 visibility means that the declaration is visible to other modules. Default
780 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]781
782 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]783 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]784 object if they are in the same shared object. Usually, hidden visibility
785 indicates that the symbol will not be placed into the dynamic symbol
786 table, so no other module (executable or shared library) can reference it
787 directly.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]788
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]789 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]790 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]791 the dynamic symbol table, but that references within the defining module
792 will bind to the local symbol. That is, the symbol cannot be overridden by
793 another module.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]794</dl>
795
796</div>
797
798<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]799<h3>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]800 <a name="namedtypes">Named Types</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]801</h3>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]802
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]803<div>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]804
805<p>LLVM IR allows you to specify name aliases for certain types. This can make
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]806 it easier to read the IR and make the IR more condensed (particularly when
807 recursive types are involved). An example of a name specification is:</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]808
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]809<pre class="doc_code">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]810%mytype = type { %mytype*, i32 }
811</pre>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]812
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]813<p>You may give a name to any <a href="#typesystem">type</a> except
Chris Lattner249b9762010-08-17 23:26:04 +0000[diff] [blame]814 "<a href="#t_void">void</a>". Type name aliases may be used anywhere a type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]815 is expected with the syntax "%mytype".</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]816
817<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]818 and that you can therefore specify multiple names for the same type. This
819 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
820 uses structural typing, the name is not part of the type. When printing out
821 LLVM IR, the printer will pick <em>one name</em> to render all types of a
822 particular shape. This means that if you have code where two different
823 source types end up having the same LLVM type, that the dumper will sometimes
824 print the "wrong" or unexpected type. This is an important design point and
825 isn't going to change.</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]826
827</div>
828
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]829<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]830<h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]831 <a name="globalvars">Global Variables</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]832</h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]833
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]834<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]835
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]836<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]837 instead of run-time. Global variables may optionally be initialized, may
838 have an explicit section to be placed in, and may have an optional explicit
839 alignment specified. A variable may be defined as "thread_local", which
840 means that it will not be shared by threads (each thread will have a
841 separated copy of the variable). A variable may be defined as a global
842 "constant," which indicates that the contents of the variable
843 will <b>never</b> be modified (enabling better optimization, allowing the
844 global data to be placed in the read-only section of an executable, etc).
845 Note that variables that need runtime initialization cannot be marked
846 "constant" as there is a store to the variable.</p>
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]847
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]848<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
849 constant, even if the final definition of the global is not. This capability
850 can be used to enable slightly better optimization of the program, but
851 requires the language definition to guarantee that optimizations based on the
852 'constantness' are valid for the translation units that do not include the
853 definition.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]854
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]855<p>As SSA values, global variables define pointer values that are in scope
856 (i.e. they dominate) all basic blocks in the program. Global variables
857 always define a pointer to their "content" type because they describe a
858 region of memory, and all memory objects in LLVM are accessed through
859 pointers.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]860
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]861<p>Global variables can be marked with <tt>unnamed_addr</tt> which indicates
862 that the address is not significant, only the content. Constants marked
Rafael Espindolaf1ed7812011-01-15 08:20:57 +0000[diff] [blame]863 like this can be merged with other constants if they have the same
864 initializer. Note that a constant with significant address <em>can</em>
865 be merged with a <tt>unnamed_addr</tt> constant, the result being a
866 constant whose address is significant.</p>
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]867
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]868<p>A global variable may be declared to reside in a target-specific numbered
869 address space. For targets that support them, address spaces may affect how
870 optimizations are performed and/or what target instructions are used to
871 access the variable. The default address space is zero. The address space
872 qualifier must precede any other attributes.</p>
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]873
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]874<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]875 supports it, it will emit globals to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]876
Chris Lattner78e00bc2010-04-28 00:13:42 +0000[diff] [blame]877<p>An explicit alignment may be specified for a global, which must be a power
878 of 2. If not present, or if the alignment is set to zero, the alignment of
879 the global is set by the target to whatever it feels convenient. If an
880 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner4bd85e42010-04-28 00:31:12 +0000[diff] [blame]881 alignment. Targets and optimizers are not allowed to over-align the global
882 if the global has an assigned section. In this case, the extra alignment
883 could be observable: for example, code could assume that the globals are
884 densely packed in their section and try to iterate over them as an array,
885 alignment padding would break this iteration.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]886
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]887<p>For example, the following defines a global in a numbered address space with
888 an initializer, section, and alignment:</p>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]889
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]890<pre class="doc_code">
Dan Gohmanaaa679b2009-01-11 00:40:00 +0000[diff] [blame]891@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]892</pre>
893
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]894</div>
895
896
897<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]898<h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]899 <a name="functionstructure">Functions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]900</h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]901
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]902<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]903
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]904<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]905 optional <a href="#linkage">linkage type</a>, an optional
906 <a href="#visibility">visibility style</a>, an optional
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]907 <a href="#callingconv">calling convention</a>,
908 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]909 <a href="#paramattrs">parameter attribute</a> for the return type, a function
910 name, a (possibly empty) argument list (each with optional
911 <a href="#paramattrs">parameter attributes</a>), optional
912 <a href="#fnattrs">function attributes</a>, an optional section, an optional
913 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
914 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]915
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]916<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
917 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]918 <a href="#visibility">visibility style</a>, an optional
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]919 <a href="#callingconv">calling convention</a>,
920 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]921 <a href="#paramattrs">parameter attribute</a> for the return type, a function
922 name, a possibly empty list of arguments, an optional alignment, and an
923 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]924
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]925<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]926 (Control Flow Graph) for the function. Each basic block may optionally start
927 with a label (giving the basic block a symbol table entry), contains a list
928 of instructions, and ends with a <a href="#terminators">terminator</a>
929 instruction (such as a branch or function return).</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]930
Chris Lattnera59fb102007-06-08 16:52:14 +0000[diff] [blame]931<p>The first basic block in a function is special in two ways: it is immediately
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]932 executed on entrance to the function, and it is not allowed to have
933 predecessor basic blocks (i.e. there can not be any branches to the entry
934 block of a function). Because the block can have no predecessors, it also
935 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]936
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]937<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]938 supports it, it will emit functions to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]939
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]940<p>An explicit alignment may be specified for a function. If not present, or if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]941 the alignment is set to zero, the alignment of the function is set by the
942 target to whatever it feels convenient. If an explicit alignment is
943 specified, the function is forced to have at least that much alignment. All
944 alignments must be a power of 2.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]945
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]946<p>If the <tt>unnamed_addr</tt> attribute is given, the address is know to not
947 be significant and two identical functions can be merged</p>.
948
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]949<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]950<pre class="doc_code">
Chris Lattner0ae02092008-10-13 16:55:18 +0000[diff] [blame]951define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]952 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
953 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
954 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
955 [<a href="#gc">gc</a>] { ... }
956</pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]957
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]958</div>
959
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]960<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]961<h3>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]962 <a name="aliasstructure">Aliases</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]963</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]964
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]965<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]966
967<p>Aliases act as "second name" for the aliasee value (which can be either
968 function, global variable, another alias or bitcast of global value). Aliases
969 may have an optional <a href="#linkage">linkage type</a>, and an
970 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]971
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]972<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]973<pre class="doc_code">
Duncan Sands7e99a942008-09-12 20:48:21 +0000[diff] [blame]974@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]975</pre>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]976
977</div>
978
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]979<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]980<h3>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]981 <a name="namedmetadatastructure">Named Metadata</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]982</h3>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]983
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]984<div>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]985
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]986<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]987 nodes</a> (but not metadata strings) are the only valid operands for
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]988 a named metadata.</p>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]989
990<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]991<pre class="doc_code">
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]992; Some unnamed metadata nodes, which are referenced by the named metadata.
993!0 = metadata !{metadata !"zero"}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]994!1 = metadata !{metadata !"one"}
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]995!2 = metadata !{metadata !"two"}
Dan Gohman58cd65f2010-07-13 19:48:13 +0000[diff] [blame]996; A named metadata.
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]997!name = !{!0, !1, !2}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]998</pre>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]999
1000</div>
1001
1002<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1003<h3>
1004 <a name="paramattrs">Parameter Attributes</a>
1005</h3>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1006
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1007<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1008
1009<p>The return type and each parameter of a function type may have a set of
1010 <i>parameter attributes</i> associated with them. Parameter attributes are
1011 used to communicate additional information about the result or parameters of
1012 a function. Parameter attributes are considered to be part of the function,
1013 not of the function type, so functions with different parameter attributes
1014 can have the same function type.</p>
1015
1016<p>Parameter attributes are simple keywords that follow the type specified. If
1017 multiple parameter attributes are needed, they are space separated. For
1018 example:</p>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1019
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1020<pre class="doc_code">
Nick Lewyckydac78d82009-02-15 23:06:14 +0000[diff] [blame]1021declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerd2597d72008-10-04 18:33:34 +0000[diff] [blame]1022declare i32 @atoi(i8 zeroext)
1023declare signext i8 @returns_signed_char()
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1024</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1025
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1026<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1027 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1028
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1029<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1030
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1031<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1032 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1033 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarichac106272011-03-16 22:20:18 +0000[diff] [blame]1034 should be zero-extended to the extent required by the target's ABI (which
1035 is usually 32-bits, but is 8-bits for a i1 on x86-64) by the caller (for a
1036 parameter) or the callee (for a return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1037
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1038 <dt><tt><b>signext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1039 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarich341c36d2011-03-17 14:21:58 +0000[diff] [blame]1040 should be sign-extended to the extent required by the target's ABI (which
1041 is usually 32-bits) by the caller (for a parameter) or the callee (for a
1042 return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1043
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1044 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1045 <dd>This indicates that this parameter or return value should be treated in a
1046 special target-dependent fashion during while emitting code for a function
1047 call or return (usually, by putting it in a register as opposed to memory,
1048 though some targets use it to distinguish between two different kinds of
1049 registers). Use of this attribute is target-specific.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1050
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1051 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Chris Lattnerd78dbee2010-11-20 23:49:06 +0000[diff] [blame]1052 <dd><p>This indicates that the pointer parameter should really be passed by
1053 value to the function. The attribute implies that a hidden copy of the
1054 pointee
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1055 is made between the caller and the callee, so the callee is unable to
1056 modify the value in the callee. This attribute is only valid on LLVM
1057 pointer arguments. It is generally used to pass structs and arrays by
1058 value, but is also valid on pointers to scalars. The copy is considered
1059 to belong to the caller not the callee (for example,
1060 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1061 <tt>byval</tt> parameters). This is not a valid attribute for return
Chris Lattnerd78dbee2010-11-20 23:49:06 +0000[diff] [blame]1062 values.</p>
1063
1064 <p>The byval attribute also supports specifying an alignment with
1065 the align attribute. It indicates the alignment of the stack slot to
1066 form and the known alignment of the pointer specified to the call site. If
1067 the alignment is not specified, then the code generator makes a
1068 target-specific assumption.</p></dd>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1069
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1070 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1071 <dd>This indicates that the pointer parameter specifies the address of a
1072 structure that is the return value of the function in the source program.
1073 This pointer must be guaranteed by the caller to be valid: loads and
1074 stores to the structure may be assumed by the callee to not to trap. This
1075 may only be applied to the first parameter. This is not a valid attribute
1076 for return values. </dd>
1077
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1078 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1079 <dd>This indicates that pointer values
1080 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohmande256292010-07-02 23:46:54 +0000[diff] [blame]1081 value do not alias pointer values which are not <i>based</i> on it,
1082 ignoring certain "irrelevant" dependencies.
1083 For a call to the parent function, dependencies between memory
1084 references from before or after the call and from those during the call
1085 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1086 return value used in that call.
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1087 The caller shares the responsibility with the callee for ensuring that
1088 these requirements are met.
1089 For further details, please see the discussion of the NoAlias response in
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]1090 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1091<br>
John McCall72ed8902010-07-06 21:07:14 +0000[diff] [blame]1092 Note that this definition of <tt>noalias</tt> is intentionally
1093 similar to the definition of <tt>restrict</tt> in C99 for function
Chris Lattner5eff9ca2010-07-06 20:51:35 +0000[diff] [blame]1094 arguments, though it is slightly weaker.
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]1095<br>
1096 For function return values, C99's <tt>restrict</tt> is not meaningful,
1097 while LLVM's <tt>noalias</tt> is.
1098 </dd>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1099
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1100 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1101 <dd>This indicates that the callee does not make any copies of the pointer
1102 that outlive the callee itself. This is not a valid attribute for return
1103 values.</dd>
1104
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1105 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1106 <dd>This indicates that the pointer parameter can be excised using the
1107 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1108 attribute for return values.</dd>
1109</dl>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1110
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1111</div>
1112
1113<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1114<h3>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1115 <a name="gc">Garbage Collector Names</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1116</h3>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1117
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1118<div>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1119
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1120<p>Each function may specify a garbage collector name, which is simply a
1121 string:</p>
1122
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1123<pre class="doc_code">
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1124define void @f() gc "name" { ... }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1125</pre>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1126
1127<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1128 collector which will cause the compiler to alter its output in order to
1129 support the named garbage collection algorithm.</p>
1130
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1131</div>
1132
1133<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1134<h3>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1135 <a name="fnattrs">Function Attributes</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1136</h3>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1137
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1138<div>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1139
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1140<p>Function attributes are set to communicate additional information about a
1141 function. Function attributes are considered to be part of the function, not
1142 of the function type, so functions with different parameter attributes can
1143 have the same function type.</p>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1144
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1145<p>Function attributes are simple keywords that follow the type specified. If
1146 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1147
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1148<pre class="doc_code">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1149define void @f() noinline { ... }
1150define void @f() alwaysinline { ... }
1151define void @f() alwaysinline optsize { ... }
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1152define void @f() optsize { ... }
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1153</pre>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1154
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1155<dl>
Charles Davisbe5557e2010-02-12 00:31:15 +0000[diff] [blame]1156 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1157 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1158 the backend should forcibly align the stack pointer. Specify the
1159 desired alignment, which must be a power of two, in parentheses.
1160
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1161 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1162 <dd>This attribute indicates that the inliner should attempt to inline this
1163 function into callers whenever possible, ignoring any active inlining size
1164 threshold for this caller.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1165
Dan Gohman8bd11f12011-06-16 16:03:13 +0000[diff] [blame]1166 <dt><tt><b>nonlazybind</b></tt></dt>
1167 <dd>This attribute suppresses lazy symbol binding for the function. This
1168 may make calls to the function faster, at the cost of extra program
1169 startup time if the function is not called during program startup.</dd>
1170
Jakob Stoklund Olesen74bb06c2010-02-06 01:16:28 +0000[diff] [blame]1171 <dt><tt><b>inlinehint</b></tt></dt>
1172 <dd>This attribute indicates that the source code contained a hint that inlining
1173 this function is desirable (such as the "inline" keyword in C/C++). It
1174 is just a hint; it imposes no requirements on the inliner.</dd>
1175
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1176 <dt><tt><b>naked</b></tt></dt>
1177 <dd>This attribute disables prologue / epilogue emission for the function.
1178 This can have very system-specific consequences.</dd>
1179
1180 <dt><tt><b>noimplicitfloat</b></tt></dt>
1181 <dd>This attributes disables implicit floating point instructions.</dd>
1182
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1183 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1184 <dd>This attribute indicates that the inliner should never inline this
1185 function in any situation. This attribute may not be used together with
1186 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1187
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1188 <dt><tt><b>noredzone</b></tt></dt>
1189 <dd>This attribute indicates that the code generator should not use a red
1190 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1191
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1192 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1193 <dd>This function attribute indicates that the function never returns
1194 normally. This produces undefined behavior at runtime if the function
1195 ever does dynamically return.</dd>
Bill Wendlinga8130172008-11-13 01:02:51 +0000[diff] [blame]1196
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1197 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1198 <dd>This function attribute indicates that the function never returns with an
1199 unwind or exceptional control flow. If the function does unwind, its
1200 runtime behavior is undefined.</dd>
Bill Wendling0f5541e2008-11-26 19:07:40 +0000[diff] [blame]1201
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1202 <dt><tt><b>optsize</b></tt></dt>
1203 <dd>This attribute suggests that optimization passes and code generator passes
1204 make choices that keep the code size of this function low, and otherwise
1205 do optimizations specifically to reduce code size.</dd>
1206
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1207 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1208 <dd>This attribute indicates that the function computes its result (or decides
1209 to unwind an exception) based strictly on its arguments, without
1210 dereferencing any pointer arguments or otherwise accessing any mutable
1211 state (e.g. memory, control registers, etc) visible to caller functions.
1212 It does not write through any pointer arguments
1213 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1214 changes any state visible to callers. This means that it cannot unwind
1215 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1216 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel310fd4a2009-06-12 19:45:19 +0000[diff] [blame]1217
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1218 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1219 <dd>This attribute indicates that the function does not write through any
1220 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1221 arguments) or otherwise modify any state (e.g. memory, control registers,
1222 etc) visible to caller functions. It may dereference pointer arguments
1223 and read state that may be set in the caller. A readonly function always
1224 returns the same value (or unwinds an exception identically) when called
1225 with the same set of arguments and global state. It cannot unwind an
1226 exception by calling the <tt>C++</tt> exception throwing methods, but may
1227 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc8ce7b082009-07-17 18:07:26 +0000[diff] [blame]1228
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1229 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1230 <dd>This attribute indicates that the function should emit a stack smashing
1231 protector. It is in the form of a "canary"&mdash;a random value placed on
1232 the stack before the local variables that's checked upon return from the
1233 function to see if it has been overwritten. A heuristic is used to
1234 determine if a function needs stack protectors or not.<br>
1235<br>
1236 If a function that has an <tt>ssp</tt> attribute is inlined into a
1237 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1238 function will have an <tt>ssp</tt> attribute.</dd>
1239
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1240 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1241 <dd>This attribute indicates that the function should <em>always</em> emit a
1242 stack smashing protector. This overrides
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1243 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1244<br>
1245 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1246 function that doesn't have an <tt>sspreq</tt> attribute or which has
1247 an <tt>ssp</tt> attribute, then the resulting function will have
1248 an <tt>sspreq</tt> attribute.</dd>
Rafael Espindola163d6752011-07-25 15:27:59 +0000[diff] [blame]1249
1250 <dt><tt><b><a name="uwtable">uwtable</a></b></tt></dt>
1251 <dd>This attribute indicates that the ABI being targeted requires that
1252 an unwind table entry be produce for this function even if we can
1253 show that no exceptions passes by it. This is normally the case for
1254 the ELF x86-64 abi, but it can be disabled for some compilation
1255 units.</dd>
1256
Rafael Espindolacc349c82011-10-03 14:45:37 +0000[diff] [blame]1257 <dt><tt><b><a name="returns_twice">returns_twice</a></b></tt></dt>
1258 <dd>This attribute indicates that this function can return
1259 twice. The C <code>setjmp</code> is an example of such a function.
1260 The compiler disables some optimizations (like tail calls) in the caller of
1261 these functions.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1262</dl>
1263
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1264</div>
1265
1266<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1267<h3>
Chris Lattner93564892006-04-08 04:40:53 +0000[diff] [blame]1268 <a name="moduleasm">Module-Level Inline Assembly</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1269</h3>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1270
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1271<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1272
1273<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1274 the GCC "file scope inline asm" blocks. These blocks are internally
1275 concatenated by LLVM and treated as a single unit, but may be separated in
1276 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1277
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1278<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1279module asm "inline asm code goes here"
1280module asm "more can go here"
1281</pre>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1282
1283<p>The strings can contain any character by escaping non-printable characters.
1284 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1285 for the number.</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1286
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1287<p>The inline asm code is simply printed to the machine code .s file when
1288 assembly code is generated.</p>
1289
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1290</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1291
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1292<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1293<h3>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1294 <a name="datalayout">Data Layout</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1295</h3>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1296
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1297<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1298
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1299<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1300 data is to be laid out in memory. The syntax for the data layout is
1301 simply:</p>
1302
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1303<pre class="doc_code">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1304target datalayout = "<i>layout specification</i>"
1305</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1306
1307<p>The <i>layout specification</i> consists of a list of specifications
1308 separated by the minus sign character ('-'). Each specification starts with
1309 a letter and may include other information after the letter to define some
1310 aspect of the data layout. The specifications accepted are as follows:</p>
1311
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1312<dl>
1313 <dt><tt>E</tt></dt>
1314 <dd>Specifies that the target lays out data in big-endian form. That is, the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1315 bits with the most significance have the lowest address location.</dd>
1316
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1317 <dt><tt>e</tt></dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1318 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1319 the bits with the least significance have the lowest address
1320 location.</dd>
1321
Lang Hamesde7ab802011-10-10 23:42:08 +0000[diff] [blame^]1322 <dt><tt>S<i>size</i></tt></dt>
1323 <dd>Specifies the natural alignment of the stack in bits. Alignment promotion
1324 of stack variables is limited to the natural stack alignment to avoid
1325 dynamic stack realignment. The stack alignment must be a multiple of
1326 8-bits, and currently defaults to 128 bits if unspecified.</dd>
1327
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1328 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1329 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1330 <i>preferred</i> alignments. All sizes are in bits. Specifying
1331 the <i>pref</i> alignment is optional. If omitted, the
1332 preceding <tt>:</tt> should be omitted too.</dd>
1333
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1334 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1335 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1336 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1337
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1338 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1339 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1340 <i>size</i>.</dd>
1341
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1342 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1343 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesence522852010-05-28 18:54:47 +0000[diff] [blame]1344 <i>size</i>. Only values of <i>size</i> that are supported by the target
1345 will work. 32 (float) and 64 (double) are supported on all targets;
1346 80 or 128 (different flavors of long double) are also supported on some
1347 targets.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1348
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1349 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1350 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1351 <i>size</i>.</dd>
1352
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1353 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1354 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1355 <i>size</i>.</dd>
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1356
1357 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1358 <dd>This specifies a set of native integer widths for the target CPU
1359 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1360 "n32:64" for PowerPC 64, or "n8:16:32:64" for X86-64. Elements of
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1361 this set are considered to support most general arithmetic
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1362 operations efficiently.</dd>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1363</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1364
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1365<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman61110ae2010-04-28 00:36:01 +0000[diff] [blame]1366 default set of specifications which are then (possibly) overridden by the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1367 specifications in the <tt>datalayout</tt> keyword. The default specifications
1368 are given in this list:</p>
1369
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1370<ul>
1371 <li><tt>E</tt> - big endian</li>
Dan Gohman8ad777d2010-02-23 02:44:03 +0000[diff] [blame]1372 <li><tt>p:64:64:64</tt> - 64-bit pointers with 64-bit alignment</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1373 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1374 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1375 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1376 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1377 <li><tt>i64:32:64</tt> - i64 has ABI alignment of 32-bits but preferred
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1378 alignment of 64-bits</li>
1379 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1380 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1381 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1382 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1383 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1384 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1385</ul>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1386
1387<p>When LLVM is determining the alignment for a given type, it uses the
1388 following rules:</p>
1389
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1390<ol>
1391 <li>If the type sought is an exact match for one of the specifications, that
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1392 specification is used.</li>
1393
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1394 <li>If no match is found, and the type sought is an integer type, then the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1395 smallest integer type that is larger than the bitwidth of the sought type
1396 is used. If none of the specifications are larger than the bitwidth then
1397 the the largest integer type is used. For example, given the default
1398 specifications above, the i7 type will use the alignment of i8 (next
1399 largest) while both i65 and i256 will use the alignment of i64 (largest
1400 specified).</li>
1401
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1402 <li>If no match is found, and the type sought is a vector type, then the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1403 largest vector type that is smaller than the sought vector type will be
1404 used as a fall back. This happens because &lt;128 x double&gt; can be
1405 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1406</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1407
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1408</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1409
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1410<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1411<h3>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1412 <a name="pointeraliasing">Pointer Aliasing Rules</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1413</h3>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1414
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1415<div>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1416
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1417<p>Any memory access must be done through a pointer value associated
Andreas Bolkae39f0332009-07-27 20:37:10 +0000[diff] [blame]1418with an address range of the memory access, otherwise the behavior
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1419is undefined. Pointer values are associated with address ranges
1420according to the following rules:</p>
1421
1422<ul>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1423 <li>A pointer value is associated with the addresses associated with
1424 any value it is <i>based</i> on.
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1425 <li>An address of a global variable is associated with the address
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1426 range of the variable's storage.</li>
1427 <li>The result value of an allocation instruction is associated with
1428 the address range of the allocated storage.</li>
1429 <li>A null pointer in the default address-space is associated with
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1430 no address.</li>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1431 <li>An integer constant other than zero or a pointer value returned
1432 from a function not defined within LLVM may be associated with address
1433 ranges allocated through mechanisms other than those provided by
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1434 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1435 allocated by mechanisms provided by LLVM.</li>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1436</ul>
1437
1438<p>A pointer value is <i>based</i> on another pointer value according
1439 to the following rules:</p>
1440
1441<ul>
1442 <li>A pointer value formed from a
1443 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1444 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1445 <li>The result value of a
1446 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1447 of the <tt>bitcast</tt>.</li>
1448 <li>A pointer value formed by an
1449 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1450 pointer values that contribute (directly or indirectly) to the
1451 computation of the pointer's value.</li>
1452 <li>The "<i>based</i> on" relationship is transitive.</li>
1453</ul>
1454
1455<p>Note that this definition of <i>"based"</i> is intentionally
1456 similar to the definition of <i>"based"</i> in C99, though it is
1457 slightly weaker.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1458
1459<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1460<tt><a href="#i_load">load</a></tt> merely indicates the size and
1461alignment of the memory from which to load, as well as the
Dan Gohman4eb47192010-06-17 19:23:50 +0000[diff] [blame]1462interpretation of the value. The first operand type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1463<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1464and alignment of the store.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1465
1466<p>Consequently, type-based alias analysis, aka TBAA, aka
1467<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1468LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1469additional information which specialized optimization passes may use
1470to implement type-based alias analysis.</p>
1471
1472</div>
1473
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1474<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1475<h3>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1476 <a name="volatile">Volatile Memory Accesses</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1477</h3>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1478
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1479<div>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1480
1481<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1482href="#i_store"><tt>store</tt></a>s, and <a
1483href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1484The optimizers must not change the number of volatile operations or change their
1485order of execution relative to other volatile operations. The optimizers
1486<i>may</i> change the order of volatile operations relative to non-volatile
1487operations. This is not Java's "volatile" and has no cross-thread
1488synchronization behavior.</p>
1489
1490</div>
1491
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1492<!-- ======================================================================= -->
1493<h3>
1494 <a name="memmodel">Memory Model for Concurrent Operations</a>
1495</h3>
1496
1497<div>
1498
1499<p>The LLVM IR does not define any way to start parallel threads of execution
1500or to register signal handlers. Nonetheless, there are platform-specific
1501ways to create them, and we define LLVM IR's behavior in their presence. This
1502model is inspired by the C++0x memory model.</p>
1503
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1504<p>For a more informal introduction to this model, see the
1505<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.
1506
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1507<p>We define a <i>happens-before</i> partial order as the least partial order
1508that</p>
1509<ul>
1510 <li>Is a superset of single-thread program order, and</li>
1511 <li>When a <i>synchronizes-with</i> <tt>b</tt>, includes an edge from
1512 <tt>a</tt> to <tt>b</tt>. <i>Synchronizes-with</i> pairs are introduced
1513 by platform-specific techniques, like pthread locks, thread
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1514 creation, thread joining, etc., and by atomic instructions.
1515 (See also <a href="#ordering">Atomic Memory Ordering Constraints</a>).
1516 </li>
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1517</ul>
1518
1519<p>Note that program order does not introduce <i>happens-before</i> edges
1520between a thread and signals executing inside that thread.</p>
1521
1522<p>Every (defined) read operation (load instructions, memcpy, atomic
1523loads/read-modify-writes, etc.) <var>R</var> reads a series of bytes written by
1524(defined) write operations (store instructions, atomic
Eli Friedmanf12e4e92011-07-22 03:04:45 +0000[diff] [blame]1525stores/read-modify-writes, memcpy, etc.). For the purposes of this section,
1526initialized globals are considered to have a write of the initializer which is
1527atomic and happens before any other read or write of the memory in question.
1528For each byte of a read <var>R</var>, <var>R<sub>byte</sub></var> may see
1529any write to the same byte, except:</p>
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1530
1531<ul>
1532 <li>If <var>write<sub>1</sub></var> happens before
1533 <var>write<sub>2</sub></var>, and <var>write<sub>2</sub></var> happens
1534 before <var>R<sub>byte</sub></var>, then <var>R<sub>byte</sub></var>
Eli Friedmanf12e4e92011-07-22 03:04:45 +0000[diff] [blame]1535 does not see <var>write<sub>1</sub></var>.
Bill Wendling537603b2011-07-31 06:45:03 +0000[diff] [blame]1536 <li>If <var>R<sub>byte</sub></var> happens before
1537 <var>write<sub>3</sub></var>, then <var>R<sub>byte</sub></var> does not
1538 see <var>write<sub>3</sub></var>.
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1539</ul>
1540
1541<p>Given that definition, <var>R<sub>byte</sub></var> is defined as follows:
1542<ul>
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1543 <li>If <var>R</var> is volatile, the result is target-dependent. (Volatile
1544 is supposed to give guarantees which can support
1545 <code>sig_atomic_t</code> in C/C++, and may be used for accesses to
1546 addresses which do not behave like normal memory. It does not generally
1547 provide cross-thread synchronization.)
1548 <li>Otherwise, if there is no write to the same byte that happens before
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1549 <var>R<sub>byte</sub></var>, <var>R<sub>byte</sub></var> returns
1550 <tt>undef</tt> for that byte.
Eli Friedmanf12e4e92011-07-22 03:04:45 +0000[diff] [blame]1551 <li>Otherwise, if <var>R<sub>byte</sub></var> may see exactly one write,
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1552 <var>R<sub>byte</sub></var> returns the value written by that
1553 write.</li>
Eli Friedmanf12e4e92011-07-22 03:04:45 +0000[diff] [blame]1554 <li>Otherwise, if <var>R</var> is atomic, and all the writes
1555 <var>R<sub>byte</sub></var> may see are atomic, it chooses one of the
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1556 values written. See the <a href="#ordering">Atomic Memory Ordering
1557 Constraints</a> section for additional constraints on how the choice
1558 is made.
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1559 <li>Otherwise <var>R<sub>byte</sub></var> returns <tt>undef</tt>.</li>
1560</ul>
1561
1562<p><var>R</var> returns the value composed of the series of bytes it read.
1563This implies that some bytes within the value may be <tt>undef</tt>
1564<b>without</b> the entire value being <tt>undef</tt>. Note that this only
1565defines the semantics of the operation; it doesn't mean that targets will
1566emit more than one instruction to read the series of bytes.</p>
1567
1568<p>Note that in cases where none of the atomic intrinsics are used, this model
1569places only one restriction on IR transformations on top of what is required
1570for single-threaded execution: introducing a store to a byte which might not
Eli Friedman4bc9f3c2011-08-02 01:15:34 +0000[diff] [blame]1571otherwise be stored is not allowed in general. (Specifically, in the case
1572where another thread might write to and read from an address, introducing a
1573store can change a load that may see exactly one write into a load that may
1574see multiple writes.)</p>
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1575
1576<!-- FIXME: This model assumes all targets where concurrency is relevant have
1577a byte-size store which doesn't affect adjacent bytes. As far as I can tell,
1578none of the backends currently in the tree fall into this category; however,
1579there might be targets which care. If there are, we want a paragraph
1580like the following:
1581
1582Targets may specify that stores narrower than a certain width are not
1583available; on such a target, for the purposes of this model, treat any
1584non-atomic write with an alignment or width less than the minimum width
1585as if it writes to the relevant surrounding bytes.
1586-->
1587
1588</div>
1589
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1590<!-- ======================================================================= -->
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]1591<h3>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1592 <a name="ordering">Atomic Memory Ordering Constraints</a>
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]1593</h3>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1594
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]1595<div>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1596
1597<p>Atomic instructions (<a href="#i_cmpxchg"><code>cmpxchg</code></a>,
Eli Friedman59b66882011-08-09 23:02:53 +0000[diff] [blame]1598<a href="#i_atomicrmw"><code>atomicrmw</code></a>,
1599<a href="#i_fence"><code>fence</code></a>,
1600<a href="#i_load"><code>atomic load</code></a>, and
Eli Friedman75362532011-08-09 23:26:12 +0000[diff] [blame]1601<a href="#i_store"><code>atomic store</code></a>) take an ordering parameter
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1602that determines which other atomic instructions on the same address they
1603<i>synchronize with</i>. These semantics are borrowed from Java and C++0x,
1604but are somewhat more colloquial. If these descriptions aren't precise enough,
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1605check those specs (see spec references in the
1606<a href="Atomic.html#introduction">atomics guide</a>).
1607<a href="#i_fence"><code>fence</code></a> instructions
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1608treat these orderings somewhat differently since they don't take an address.
1609See that instruction's documentation for details.</p>
1610
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1611<p>For a simpler introduction to the ordering constraints, see the
1612<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.</p>
1613
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1614<dl>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1615<dt><code>unordered</code></dt>
1616<dd>The set of values that can be read is governed by the happens-before
1617partial order. A value cannot be read unless some operation wrote it.
1618This is intended to provide a guarantee strong enough to model Java's
1619non-volatile shared variables. This ordering cannot be specified for
1620read-modify-write operations; it is not strong enough to make them atomic
1621in any interesting way.</dd>
1622<dt><code>monotonic</code></dt>
1623<dd>In addition to the guarantees of <code>unordered</code>, there is a single
1624total order for modifications by <code>monotonic</code> operations on each
1625address. All modification orders must be compatible with the happens-before
1626order. There is no guarantee that the modification orders can be combined to
1627a global total order for the whole program (and this often will not be
1628possible). The read in an atomic read-modify-write operation
1629(<a href="#i_cmpxchg"><code>cmpxchg</code></a> and
1630<a href="#i_atomicrmw"><code>atomicrmw</code></a>)
1631reads the value in the modification order immediately before the value it
1632writes. If one atomic read happens before another atomic read of the same
1633address, the later read must see the same value or a later value in the
1634address's modification order. This disallows reordering of
1635<code>monotonic</code> (or stronger) operations on the same address. If an
1636address is written <code>monotonic</code>ally by one thread, and other threads
1637<code>monotonic</code>ally read that address repeatedly, the other threads must
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1638eventually see the write. This corresponds to the C++0x/C1x
1639<code>memory_order_relaxed</code>.</dd>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1640<dt><code>acquire</code></dt>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1641<dd>In addition to the guarantees of <code>monotonic</code>,
Eli Friedman0cb3b562011-08-24 20:28:39 +0000[diff] [blame]1642a <i>synchronizes-with</i> edge may be formed with a <code>release</code>
1643operation. This is intended to model C++'s <code>memory_order_acquire</code>.</dd>
1644<dt><code>release</code></dt>
1645<dd>In addition to the guarantees of <code>monotonic</code>, if this operation
1646writes a value which is subsequently read by an <code>acquire</code> operation,
1647it <i>synchronizes-with</i> that operation. (This isn't a complete
1648description; see the C++0x definition of a release sequence.) This corresponds
1649to the C++0x/C1x <code>memory_order_release</code>.</dd>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1650<dt><code>acq_rel</code> (acquire+release)</dt><dd>Acts as both an
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1651<code>acquire</code> and <code>release</code> operation on its address.
1652This corresponds to the C++0x/C1x <code>memory_order_acq_rel</code>.</dd>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1653<dt><code>seq_cst</code> (sequentially consistent)</dt><dd>
1654<dd>In addition to the guarantees of <code>acq_rel</code>
1655(<code>acquire</code> for an operation which only reads, <code>release</code>
1656for an operation which only writes), there is a global total order on all
1657sequentially-consistent operations on all addresses, which is consistent with
1658the <i>happens-before</i> partial order and with the modification orders of
1659all the affected addresses. Each sequentially-consistent read sees the last
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1660preceding write to the same address in this global order. This corresponds
1661to the C++0x/C1x <code>memory_order_seq_cst</code> and Java volatile.</dd>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1662</dl>
1663
1664<p id="singlethread">If an atomic operation is marked <code>singlethread</code>,
1665it only <i>synchronizes with</i> or participates in modification and seq_cst
1666total orderings with other operations running in the same thread (for example,
1667in signal handlers).</p>
1668
1669</div>
1670
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1671</div>
1672
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1673<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1674<h2><a name="typesystem">Type System</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1675<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1676
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1677<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1678
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1679<p>The LLVM type system is one of the most important features of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1680 intermediate representation. Being typed enables a number of optimizations
1681 to be performed on the intermediate representation directly, without having
1682 to do extra analyses on the side before the transformation. A strong type
1683 system makes it easier to read the generated code and enables novel analyses
1684 and transformations that are not feasible to perform on normal three address
1685 code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1686
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1687<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1688<h3>
1689 <a name="t_classifications">Type Classifications</a>
1690</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1691
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1692<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1693
1694<p>The types fall into a few useful classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1695
1696<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1697 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1698 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1699 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1700 <td><a href="#t_integer">integer</a></td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1701 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1702 </tr>
1703 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1704 <td><a href="#t_floating">floating point</a></td>
1705 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1706 </tr>
1707 <tr>
1708 <td><a name="t_firstclass">first class</a></td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1709 <td><a href="#t_integer">integer</a>,
1710 <a href="#t_floating">floating point</a>,
1711 <a href="#t_pointer">pointer</a>,
Dan Gohman08783a882008-06-18 18:42:13 +0000[diff] [blame]1712 <a href="#t_vector">vector</a>,
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]1713 <a href="#t_struct">structure</a>,
1714 <a href="#t_array">array</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1715 <a href="#t_label">label</a>,
1716 <a href="#t_metadata">metadata</a>.
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1717 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1718 </tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1719 <tr>
1720 <td><a href="#t_primitive">primitive</a></td>
1721 <td><a href="#t_label">label</a>,
1722 <a href="#t_void">void</a>,
Tobias Grosser4c8c95b2010-12-28 20:29:31 +0000[diff] [blame]1723 <a href="#t_integer">integer</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1724 <a href="#t_floating">floating point</a>,
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1725 <a href="#t_x86mmx">x86mmx</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1726 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1727 </tr>
1728 <tr>
1729 <td><a href="#t_derived">derived</a></td>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1730 <td><a href="#t_array">array</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1731 <a href="#t_function">function</a>,
1732 <a href="#t_pointer">pointer</a>,
1733 <a href="#t_struct">structure</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1734 <a href="#t_vector">vector</a>,
1735 <a href="#t_opaque">opaque</a>.
Dan Gohman93bf60d2008-10-14 16:32:04 +0000[diff] [blame]1736 </td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1737 </tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1738 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1739</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1740
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1741<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1742 important. Values of these types are the only ones which can be produced by
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1743 instructions.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1744
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1745</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1746
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1747<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1748<h3>
1749 <a name="t_primitive">Primitive Types</a>
1750</h3>
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1751
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1752<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1753
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1754<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1755 system.</p>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1756
1757<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1758<h4>
1759 <a name="t_integer">Integer Type</a>
1760</h4>
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1761
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1762<div>
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1763
1764<h5>Overview:</h5>
1765<p>The integer type is a very simple type that simply specifies an arbitrary
1766 bit width for the integer type desired. Any bit width from 1 bit to
1767 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1768
1769<h5>Syntax:</h5>
1770<pre>
1771 iN
1772</pre>
1773
1774<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1775 value.</p>
1776
1777<h5>Examples:</h5>
1778<table class="layout">
1779 <tr class="layout">
1780 <td class="left"><tt>i1</tt></td>
1781 <td class="left">a single-bit integer.</td>
1782 </tr>
1783 <tr class="layout">
1784 <td class="left"><tt>i32</tt></td>
1785 <td class="left">a 32-bit integer.</td>
1786 </tr>
1787 <tr class="layout">
1788 <td class="left"><tt>i1942652</tt></td>
1789 <td class="left">a really big integer of over 1 million bits.</td>
1790 </tr>
1791</table>
1792
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1793</div>
1794
1795<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1796<h4>
1797 <a name="t_floating">Floating Point Types</a>
1798</h4>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1799
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1800<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1801
1802<table>
1803 <tbody>
1804 <tr><th>Type</th><th>Description</th></tr>
1805 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1806 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1807 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1808 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1809 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1810 </tbody>
1811</table>
1812
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1813</div>
1814
1815<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1816<h4>
1817 <a name="t_x86mmx">X86mmx Type</a>
1818</h4>
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1819
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1820<div>
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1821
1822<h5>Overview:</h5>
1823<p>The x86mmx type represents a value held in an MMX register on an x86 machine. The operations allowed on it are quite limited: parameters and return values, load and store, and bitcast. User-specified MMX instructions are represented as intrinsic or asm calls with arguments and/or results of this type. There are no arrays, vectors or constants of this type.</p>
1824
1825<h5>Syntax:</h5>
1826<pre>
Dale Johannesenb1f0ff12010-10-01 01:07:02 +0000[diff] [blame]1827 x86mmx
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1828</pre>
1829
1830</div>
1831
1832<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1833<h4>
1834 <a name="t_void">Void Type</a>
1835</h4>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1836
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1837<div>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1838
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1839<h5>Overview:</h5>
1840<p>The void type does not represent any value and has no size.</p>
1841
1842<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1843<pre>
1844 void
1845</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1846
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1847</div>
1848
1849<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1850<h4>
1851 <a name="t_label">Label Type</a>
1852</h4>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1853
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1854<div>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1855
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1856<h5>Overview:</h5>
1857<p>The label type represents code labels.</p>
1858
1859<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1860<pre>
1861 label
1862</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1863
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1864</div>
1865
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1866<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1867<h4>
1868 <a name="t_metadata">Metadata Type</a>
1869</h4>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1870
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1871<div>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1872
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1873<h5>Overview:</h5>
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1874<p>The metadata type represents embedded metadata. No derived types may be
1875 created from metadata except for <a href="#t_function">function</a>
1876 arguments.
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1877
1878<h5>Syntax:</h5>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1879<pre>
1880 metadata
1881</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1882
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1883</div>
1884
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1885</div>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1886
1887<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1888<h3>
1889 <a name="t_derived">Derived Types</a>
1890</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1891
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1892<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1893
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1894<p>The real power in LLVM comes from the derived types in the system. This is
1895 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1896 useful types. Each of these types contain one or more element types which
1897 may be a primitive type, or another derived type. For example, it is
1898 possible to have a two dimensional array, using an array as the element type
1899 of another array.</p>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1900
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]1901</div>
1902
1903
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1904<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1905<h4>
1906 <a name="t_aggregate">Aggregate Types</a>
1907</h4>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1908
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1909<div>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1910
1911<p>Aggregate Types are a subset of derived types that can contain multiple
1912 member types. <a href="#t_array">Arrays</a>,
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]1913 <a href="#t_struct">structs</a>, and <a href="#t_vector">vectors</a> are
1914 aggregate types.</p>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1915
1916</div>
1917
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1918<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1919<h4>
1920 <a name="t_array">Array Type</a>
1921</h4>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1922
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1923<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1924
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1925<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1926<p>The array type is a very simple derived type that arranges elements
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1927 sequentially in memory. The array type requires a size (number of elements)
1928 and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1929
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1930<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1931<pre>
1932 [&lt;# elements&gt; x &lt;elementtype&gt;]
1933</pre>
1934
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1935<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1936 be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1937
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1938<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1939<table class="layout">
1940 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1941 <td class="left"><tt>[40 x i32]</tt></td>
1942 <td class="left">Array of 40 32-bit integer values.</td>
1943 </tr>
1944 <tr class="layout">
1945 <td class="left"><tt>[41 x i32]</tt></td>
1946 <td class="left">Array of 41 32-bit integer values.</td>
1947 </tr>
1948 <tr class="layout">
1949 <td class="left"><tt>[4 x i8]</tt></td>
1950 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1951 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1952</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1953<p>Here are some examples of multidimensional arrays:</p>
1954<table class="layout">
1955 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1956 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1957 <td class="left">3x4 array of 32-bit integer values.</td>
1958 </tr>
1959 <tr class="layout">
1960 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1961 <td class="left">12x10 array of single precision floating point values.</td>
1962 </tr>
1963 <tr class="layout">
1964 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1965 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1966 </tr>
1967</table>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1968
Dan Gohmanc74bc282009-11-09 19:01:53 +0000[diff] [blame]1969<p>There is no restriction on indexing beyond the end of the array implied by
1970 a static type (though there are restrictions on indexing beyond the bounds
1971 of an allocated object in some cases). This means that single-dimension
1972 'variable sized array' addressing can be implemented in LLVM with a zero
1973 length array type. An implementation of 'pascal style arrays' in LLVM could
1974 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1975
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1976</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1977
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1978<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1979<h4>
1980 <a name="t_function">Function Type</a>
1981</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1982
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1983<div>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1984
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1985<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1986<p>The function type can be thought of as a function signature. It consists of
1987 a return type and a list of formal parameter types. The return type of a
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]1988 function type is a first class type or a void type.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1989
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1990<h5>Syntax:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1991<pre>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]1992 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1993</pre>
1994
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1995<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1996 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1997 which indicates that the function takes a variable number of arguments.
1998 Variable argument functions can access their arguments with
1999 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]2000 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]2001 <a href="#t_label">label</a>.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2002
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2003<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2004<table class="layout">
2005 <tr class="layout">
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]2006 <td class="left"><tt>i32 (i32)</tt></td>
2007 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2008 </td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]2009 </tr><tr class="layout">
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]2010 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencer655dcc62006-12-31 07:20:23 +0000[diff] [blame]2011 </tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2012 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]2013 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
2014 returning <tt>float</tt>.
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]2015 </td>
2016 </tr><tr class="layout">
2017 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2018 <td class="left">A vararg function that takes at least one
2019 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
2020 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]2021 LLVM.
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2022 </td>
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]2023 </tr><tr class="layout">
2024 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]2025 <td class="left">A function taking an <tt>i32</tt>, returning a
2026 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]2027 </td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2028 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2029</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2030
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2031</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2032
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2033<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2034<h4>
2035 <a name="t_struct">Structure Type</a>
2036</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2037
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2038<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2039
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2040<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2041<p>The structure type is used to represent a collection of data members together
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2042 in memory. The elements of a structure may be any type that has a size.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2043
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]2044<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
2045 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
2046 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
2047 Structures in registers are accessed using the
2048 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
2049 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2050
2051<p>Structures may optionally be "packed" structures, which indicate that the
2052 alignment of the struct is one byte, and that there is no padding between
Chris Lattner190552d2011-08-12 17:31:02 +0000[diff] [blame]2053 the elements. In non-packed structs, padding between field types is inserted
2054 as defined by the TargetData string in the module, which is required to match
2055 what the underlying processor expects.</p>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2056
Chris Lattner190552d2011-08-12 17:31:02 +0000[diff] [blame]2057<p>Structures can either be "literal" or "identified". A literal structure is
2058 defined inline with other types (e.g. <tt>{i32, i32}*</tt>) whereas identified
2059 types are always defined at the top level with a name. Literal types are
2060 uniqued by their contents and can never be recursive or opaque since there is
Chris Lattner32531732011-08-12 18:12:40 +0000[diff] [blame]2061 no way to write one. Identified types can be recursive, can be opaqued, and are
Chris Lattner190552d2011-08-12 17:31:02 +0000[diff] [blame]2062 never uniqued.
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2063</p>
2064
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2065<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2066<pre>
Chris Lattner190552d2011-08-12 17:31:02 +0000[diff] [blame]2067 %T1 = type { &lt;type list&gt; } <i>; Identified normal struct type</i>
2068 %T2 = type &lt;{ &lt;type list&gt; }&gt; <i>; Identified packed struct type</i>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2069</pre>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2070
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2071<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2072<table class="layout">
2073 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2074 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
2075 <td class="left">A triple of three <tt>i32</tt> values</td>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2076 </tr>
2077 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2078 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
2079 <td class="left">A pair, where the first element is a <tt>float</tt> and the
2080 second element is a <a href="#t_pointer">pointer</a> to a
2081 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
2082 an <tt>i32</tt>.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2083 </tr>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2084 <tr class="layout">
2085 <td class="left"><tt>&lt;{ i8, i32 }&gt;</tt></td>
2086 <td class="left">A packed struct known to be 5 bytes in size.</td>
2087 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2088</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]2089
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2090</div>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2091
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2092<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2093<h4>
Chris Lattner2a843822011-07-23 19:59:08 +0000[diff] [blame]2094 <a name="t_opaque">Opaque Structure Types</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2095</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2096
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2097<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2098
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2099<h5>Overview:</h5>
Chris Lattner2a843822011-07-23 19:59:08 +0000[diff] [blame]2100<p>Opaque structure types are used to represent named structure types that do
2101 not have a body specified. This corresponds (for example) to the C notion of
2102 a forward declared structure.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2103
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2104<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2105<pre>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2106 %X = type opaque
2107 %52 = type opaque
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2108</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2109
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2110<h5>Examples:</h5>
2111<table class="layout">
2112 <tr class="layout">
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2113 <td class="left"><tt>opaque</tt></td>
2114 <td class="left">An opaque type.</td>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2115 </tr>
2116</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2117
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2118</div>
2119
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2120
2121
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2122<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2123<h4>
2124 <a name="t_pointer">Pointer Type</a>
2125</h4>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]2126
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2127<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2128
2129<h5>Overview:</h5>
Dan Gohman88481112010-02-25 16:50:07 +0000[diff] [blame]2130<p>The pointer type is used to specify memory locations.
2131 Pointers are commonly used to reference objects in memory.</p>
2132
2133<p>Pointer types may have an optional address space attribute defining the
2134 numbered address space where the pointed-to object resides. The default
2135 address space is number zero. The semantics of non-zero address
2136 spaces are target-specific.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2137
2138<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
2139 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]2140
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2141<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2142<pre>
2143 &lt;type&gt; *
2144</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2145
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2146<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2147<table class="layout">
2148 <tr class="layout">
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2149 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2150 <td class="left">A <a href="#t_pointer">pointer</a> to <a
2151 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
2152 </tr>
2153 <tr class="layout">
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]2154 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2155 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2156 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2157 <tt>i32</tt>.</td>
2158 </tr>
2159 <tr class="layout">
2160 <td class="left"><tt>i32 addrspace(5)*</tt></td>
2161 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
2162 that resides in address space #5.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2163 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2164</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2165
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2166</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2167
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2168<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2169<h4>
2170 <a name="t_vector">Vector Type</a>
2171</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2172
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2173<div>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2174
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2175<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2176<p>A vector type is a simple derived type that represents a vector of elements.
2177 Vector types are used when multiple primitive data are operated in parallel
2178 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sands31c0e0e2009-11-27 13:38:03 +0000[diff] [blame]2179 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2180 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2181
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2182<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2183<pre>
2184 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
2185</pre>
2186
Chris Lattnerf11031a2010-10-10 18:20:35 +0000[diff] [blame]2187<p>The number of elements is a constant integer value larger than 0; elementtype
2188 may be any integer or floating point type. Vectors of size zero are not
2189 allowed, and pointers are not allowed as the element type.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2190
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2191<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2192<table class="layout">
2193 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2194 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
2195 <td class="left">Vector of 4 32-bit integer values.</td>
2196 </tr>
2197 <tr class="layout">
2198 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
2199 <td class="left">Vector of 8 32-bit floating-point values.</td>
2200 </tr>
2201 <tr class="layout">
2202 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
2203 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2204 </tr>
2205</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]2206
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2207</div>
2208
Bill Wendlingae8b5ea2011-07-31 06:47:33 +0000[diff] [blame]2209</div>
2210
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2211<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2212<h2><a name="constants">Constants</a></h2>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2213<!-- *********************************************************************** -->
2214
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2215<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2216
2217<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2218 them all and their syntax.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2219
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2220<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2221<h3>
2222 <a name="simpleconstants">Simple Constants</a>
2223</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2224
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2225<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2226
2227<dl>
2228 <dt><b>Boolean constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2229 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]2230 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2231
2232 <dt><b>Integer constants</b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2233 <dd>Standard integers (such as '4') are constants of
2234 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2235 with integer types.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2236
2237 <dt><b>Floating point constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2238 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2239 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2240 notation (see below). The assembler requires the exact decimal value of a
2241 floating-point constant. For example, the assembler accepts 1.25 but
2242 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2243 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2244
2245 <dt><b>Null pointer constants</b></dt>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2246 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2247 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2248</dl>
2249
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2250<p>The one non-intuitive notation for constants is the hexadecimal form of
2251 floating point constants. For example, the form '<tt>double
2252 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2253 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2254 constants are required (and the only time that they are generated by the
2255 disassembler) is when a floating point constant must be emitted but it cannot
2256 be represented as a decimal floating point number in a reasonable number of
2257 digits. For example, NaN's, infinities, and other special values are
2258 represented in their IEEE hexadecimal format so that assembly and disassembly
2259 do not cause any bits to change in the constants.</p>
2260
Dale Johannesencd4a3012009-02-11 22:14:51 +0000[diff] [blame]2261<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2262 represented using the 16-digit form shown above (which matches the IEEE754
2263 representation for double); float values must, however, be exactly
2264 representable as IEE754 single precision. Hexadecimal format is always used
2265 for long double, and there are three forms of long double. The 80-bit format
2266 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2267 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2268 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2269 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2270 currently supported target uses this format. Long doubles will only work if
2271 they match the long double format on your target. All hexadecimal formats
2272 are big-endian (sign bit at the left).</p>
2273
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]2274<p>There are no constants of type x86mmx.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2275</div>
2276
2277<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2278<h3>
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]2279<a name="aggregateconstants"></a> <!-- old anchor -->
2280<a name="complexconstants">Complex Constants</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2281</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2282
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2283<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2284
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]2285<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2286 constants and smaller complex constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2287
2288<dl>
2289 <dt><b>Structure constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2290 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2291 type definitions (a comma separated list of elements, surrounded by braces
2292 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2293 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2294 Structure constants must have <a href="#t_struct">structure type</a>, and
2295 the number and types of elements must match those specified by the
2296 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2297
2298 <dt><b>Array constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2299 <dd>Array constants are represented with notation similar to array type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2300 definitions (a comma separated list of elements, surrounded by square
2301 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2302 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2303 the number and types of elements must match those specified by the
2304 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2305
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2306 <dt><b>Vector constants</b></dt>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2307 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2308 definitions (a comma separated list of elements, surrounded by
2309 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2310 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2311 have <a href="#t_vector">vector type</a>, and the number and types of
2312 elements must match those specified by the type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2313
2314 <dt><b>Zero initialization</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2315 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]2316 value to zero of <em>any</em> type, including scalar and
2317 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2318 This is often used to avoid having to print large zero initializers
2319 (e.g. for large arrays) and is always exactly equivalent to using explicit
2320 zero initializers.</dd>
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2321
2322 <dt><b>Metadata node</b></dt>
Nick Lewycky8e2c4f42009-05-30 16:08:30 +0000[diff] [blame]2323 <dd>A metadata node is a structure-like constant with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2324 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2325 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2326 be interpreted as part of the instruction stream, metadata is a place to
2327 attach additional information such as debug info.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2328</dl>
2329
2330</div>
2331
2332<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2333<h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2334 <a name="globalconstants">Global Variable and Function Addresses</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2335</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2336
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2337<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2338
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2339<p>The addresses of <a href="#globalvars">global variables</a>
2340 and <a href="#functionstructure">functions</a> are always implicitly valid
2341 (link-time) constants. These constants are explicitly referenced when
2342 the <a href="#identifiers">identifier for the global</a> is used and always
2343 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2344 legal LLVM file:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2345
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2346<pre class="doc_code">
Chris Lattner00538a12007-06-06 18:28:13 +0000[diff] [blame]2347@X = global i32 17
2348@Y = global i32 42
2349@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2350</pre>
2351
2352</div>
2353
2354<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2355<h3>
2356 <a name="undefvalues">Undefined Values</a>
2357</h3>
2358
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2359<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2360
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2361<p>The string '<tt>undef</tt>' can be used anywhere a constant is expected, and
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]2362 indicates that the user of the value may receive an unspecified bit-pattern.
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2363 Undefined values may be of any type (other than '<tt>label</tt>'
2364 or '<tt>void</tt>') and be used anywhere a constant is permitted.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2365
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2366<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2367 program is well defined no matter what value is used. This gives the
2368 compiler more freedom to optimize. Here are some examples of (potentially
2369 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2370
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2371
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2372<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2373 %A = add %X, undef
2374 %B = sub %X, undef
2375 %C = xor %X, undef
2376Safe:
2377 %A = undef
2378 %B = undef
2379 %C = undef
2380</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2381
2382<p>This is safe because all of the output bits are affected by the undef bits.
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2383 Any output bit can have a zero or one depending on the input bits.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2384
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2385<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2386 %A = or %X, undef
2387 %B = and %X, undef
2388Safe:
2389 %A = -1
2390 %B = 0
2391Unsafe:
2392 %A = undef
2393 %B = undef
2394</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2395
2396<p>These logical operations have bits that are not always affected by the input.
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2397 For example, if <tt>%X</tt> has a zero bit, then the output of the
2398 '<tt>and</tt>' operation will always be a zero for that bit, no matter what
2399 the corresponding bit from the '<tt>undef</tt>' is. As such, it is unsafe to
2400 optimize or assume that the result of the '<tt>and</tt>' is '<tt>undef</tt>'.
2401 However, it is safe to assume that all bits of the '<tt>undef</tt>' could be
2402 0, and optimize the '<tt>and</tt>' to 0. Likewise, it is safe to assume that
2403 all the bits of the '<tt>undef</tt>' operand to the '<tt>or</tt>' could be
2404 set, allowing the '<tt>or</tt>' to be folded to -1.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2405
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2406<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2407 %A = select undef, %X, %Y
2408 %B = select undef, 42, %Y
2409 %C = select %X, %Y, undef
2410Safe:
2411 %A = %X (or %Y)
2412 %B = 42 (or %Y)
2413 %C = %Y
2414Unsafe:
2415 %A = undef
2416 %B = undef
2417 %C = undef
2418</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2419
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2420<p>This set of examples shows that undefined '<tt>select</tt>' (and conditional
2421 branch) conditions can go <em>either way</em>, but they have to come from one
2422 of the two operands. In the <tt>%A</tt> example, if <tt>%X</tt> and
2423 <tt>%Y</tt> were both known to have a clear low bit, then <tt>%A</tt> would
2424 have to have a cleared low bit. However, in the <tt>%C</tt> example, the
2425 optimizer is allowed to assume that the '<tt>undef</tt>' operand could be the
2426 same as <tt>%Y</tt>, allowing the whole '<tt>select</tt>' to be
2427 eliminated.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2428
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2429<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2430 %A = xor undef, undef
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2431
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2432 %B = undef
2433 %C = xor %B, %B
2434
2435 %D = undef
2436 %E = icmp lt %D, 4
2437 %F = icmp gte %D, 4
2438
2439Safe:
2440 %A = undef
2441 %B = undef
2442 %C = undef
2443 %D = undef
2444 %E = undef
2445 %F = undef
2446</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2447
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2448<p>This example points out that two '<tt>undef</tt>' operands are not
2449 necessarily the same. This can be surprising to people (and also matches C
2450 semantics) where they assume that "<tt>X^X</tt>" is always zero, even
2451 if <tt>X</tt> is undefined. This isn't true for a number of reasons, but the
2452 short answer is that an '<tt>undef</tt>' "variable" can arbitrarily change
2453 its value over its "live range". This is true because the variable doesn't
2454 actually <em>have a live range</em>. Instead, the value is logically read
2455 from arbitrary registers that happen to be around when needed, so the value
2456 is not necessarily consistent over time. In fact, <tt>%A</tt> and <tt>%C</tt>
2457 need to have the same semantics or the core LLVM "replace all uses with"
2458 concept would not hold.</p>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2459
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2460<pre class="doc_code">
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2461 %A = fdiv undef, %X
2462 %B = fdiv %X, undef
2463Safe:
2464 %A = undef
2465b: unreachable
2466</pre>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2467
2468<p>These examples show the crucial difference between an <em>undefined
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2469 value</em> and <em>undefined behavior</em>. An undefined value (like
2470 '<tt>undef</tt>') is allowed to have an arbitrary bit-pattern. This means that
2471 the <tt>%A</tt> operation can be constant folded to '<tt>undef</tt>', because
2472 the '<tt>undef</tt>' could be an SNaN, and <tt>fdiv</tt> is not (currently)
2473 defined on SNaN's. However, in the second example, we can make a more
2474 aggressive assumption: because the <tt>undef</tt> is allowed to be an
2475 arbitrary value, we are allowed to assume that it could be zero. Since a
2476 divide by zero has <em>undefined behavior</em>, we are allowed to assume that
2477 the operation does not execute at all. This allows us to delete the divide and
2478 all code after it. Because the undefined operation "can't happen", the
2479 optimizer can assume that it occurs in dead code.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2480
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2481<pre class="doc_code">
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2482a: store undef -> %X
2483b: store %X -> undef
2484Safe:
2485a: &lt;deleted&gt;
2486b: unreachable
2487</pre>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2488
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2489<p>These examples reiterate the <tt>fdiv</tt> example: a store <em>of</em> an
2490 undefined value can be assumed to not have any effect; we can assume that the
2491 value is overwritten with bits that happen to match what was already there.
2492 However, a store <em>to</em> an undefined location could clobber arbitrary
2493 memory, therefore, it has undefined behavior.</p>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2494
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2495</div>
2496
2497<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2498<h3>
2499 <a name="trapvalues">Trap Values</a>
2500</h3>
2501
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2502<div>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2503
Dan Gohmanb2a709b2010-04-26 20:21:21 +0000[diff] [blame]2504<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2505 instead of representing an unspecified bit pattern, they represent the
2506 fact that an instruction or constant expression which cannot evoke side
2507 effects has nevertheless detected a condition which results in undefined
Dan Gohmanb2a709b2010-04-26 20:21:21 +0000[diff] [blame]2508 behavior.</p>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2509
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2510<p>There is currently no way of representing a trap value in the IR; they
Dan Gohmanac355aa2010-05-03 14:51:43 +0000[diff] [blame]2511 only exist when produced by operations such as
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2512 <a href="#i_add"><tt>add</tt></a> with the <tt>nsw</tt> flag.</p>
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2513
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2514<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2515
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2516<ul>
2517<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2518 their operands.</li>
2519
2520<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2521 to their dynamic predecessor basic block.</li>
2522
2523<li>Function arguments depend on the corresponding actual argument values in
2524 the dynamic callers of their functions.</li>
2525
2526<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2527 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2528 control back to them.</li>
2529
Dan Gohman7292a752010-05-03 14:55:22 +0000[diff] [blame]2530<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
2531 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_unwind"><tt>unwind</tt></a>,
2532 or exception-throwing call instructions that dynamically transfer control
2533 back to them.</li>
2534
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2535<li>Non-volatile loads and stores depend on the most recent stores to all of the
2536 referenced memory addresses, following the order in the IR
2537 (including loads and stores implied by intrinsics such as
2538 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2539
Dan Gohman3513ea52010-05-03 14:59:34 +0000[diff] [blame]2540<!-- TODO: In the case of multiple threads, this only applies if the store
2541 "happens-before" the load or store. -->
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2542
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2543<!-- TODO: floating-point exception state -->
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2544
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2545<li>An instruction with externally visible side effects depends on the most
2546 recent preceding instruction with externally visible side effects, following
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]2547 the order in the IR. (This includes
2548 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2549
Dan Gohman7292a752010-05-03 14:55:22 +0000[diff] [blame]2550<li>An instruction <i>control-depends</i> on a
2551 <a href="#terminators">terminator instruction</a>
2552 if the terminator instruction has multiple successors and the instruction
2553 is always executed when control transfers to one of the successors, and
Chris Lattner0ab5e2c2011-04-15 05:18:47 +0000[diff] [blame]2554 may not be executed when control is transferred to another.</li>
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2555
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2556<li>Additionally, an instruction also <i>control-depends</i> on a terminator
2557 instruction if the set of instructions it otherwise depends on would be
Chris Lattner0ab5e2c2011-04-15 05:18:47 +0000[diff] [blame]2558 different if the terminator had transferred control to a different
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2559 successor.</li>
2560
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2561<li>Dependence is transitive.</li>
2562
2563</ul>
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2564
2565<p>Whenever a trap value is generated, all values which depend on it evaluate
2566 to trap. If they have side effects, the evoke their side effects as if each
2567 operand with a trap value were undef. If they have externally-visible side
2568 effects, the behavior is undefined.</p>
2569
2570<p>Here are some examples:</p>
Dan Gohman48a25882010-04-26 20:54:53 +0000[diff] [blame]2571
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2572<pre class="doc_code">
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2573entry:
2574 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2575 %still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2576 %trap_yet_again = getelementptr i32* @h, i32 %still_trap
2577 store i32 0, i32* %trap_yet_again ; undefined behavior
2578
2579 store i32 %trap, i32* @g ; Trap value conceptually stored to memory.
2580 %trap2 = load i32* @g ; Returns a trap value, not just undef.
2581
2582 volatile store i32 %trap, i32* @g ; External observation; undefined behavior.
2583
2584 %narrowaddr = bitcast i32* @g to i16*
2585 %wideaddr = bitcast i32* @g to i64*
Nick Lewycky9c876bf2011-05-16 19:29:30 +0000[diff] [blame]2586 %trap3 = load i16* %narrowaddr ; Returns a trap value.
2587 %trap4 = load i64* %wideaddr ; Returns a trap value.
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2588
Nick Lewycky9c876bf2011-05-16 19:29:30 +0000[diff] [blame]2589 %cmp = icmp slt i32 %trap, 0 ; Returns a trap value.
2590 br i1 %cmp, label %true, label %end ; Branch to either destination.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2591
2592true:
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2593 volatile store i32 0, i32* @g ; This is control-dependent on %cmp, so
2594 ; it has undefined behavior.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2595 br label %end
2596
2597end:
2598 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2599 ; Both edges into this PHI are
2600 ; control-dependent on %cmp, so this
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2601 ; always results in a trap value.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2602
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2603 volatile store i32 0, i32* @g ; This would depend on the store in %true
2604 ; if %cmp is true, or the store in %entry
2605 ; otherwise, so this is undefined behavior.
2606
Nick Lewycky9c876bf2011-05-16 19:29:30 +0000[diff] [blame]2607 br i1 %cmp, label %second_true, label %second_end
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2608 ; The same branch again, but this time the
2609 ; true block doesn't have side effects.
2610
2611second_true:
2612 ; No side effects!
Nick Lewycky9c876bf2011-05-16 19:29:30 +0000[diff] [blame]2613 ret void
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2614
2615second_end:
2616 volatile store i32 0, i32* @g ; This time, the instruction always depends
2617 ; on the store in %end. Also, it is
2618 ; control-equivalent to %end, so this is
Nick Lewycky9c876bf2011-05-16 19:29:30 +0000[diff] [blame]2619 ; well-defined (again, ignoring earlier
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2620 ; undefined behavior in this example).
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2621</pre>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2622
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2623</div>
2624
2625<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2626<h3>
2627 <a name="blockaddress">Addresses of Basic Blocks</a>
2628</h3>
2629
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2630<div>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2631
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2632<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2633
2634<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner5c5f0ac2009-10-27 21:49:40 +0000[diff] [blame]2635 basic block in the specified function, and always has an i8* type. Taking
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2636 the address of the entry block is illegal.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2637
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2638<p>This value only has defined behavior when used as an operand to the
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2639 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction, or for
2640 comparisons against null. Pointer equality tests between labels addresses
2641 results in undefined behavior &mdash; though, again, comparison against null
2642 is ok, and no label is equal to the null pointer. This may be passed around
2643 as an opaque pointer sized value as long as the bits are not inspected. This
2644 allows <tt>ptrtoint</tt> and arithmetic to be performed on these values so
2645 long as the original value is reconstituted before the <tt>indirectbr</tt>
2646 instruction.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2647
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2648<p>Finally, some targets may provide defined semantics when using the value as
2649 the operand to an inline assembly, but that is target specific.</p>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2650
2651</div>
2652
2653
2654<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2655<h3>
2656 <a name="constantexprs">Constant Expressions</a>
2657</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2658
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2659<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2660
2661<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2662 to be used as constants. Constant expressions may be of
2663 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2664 operation that does not have side effects (e.g. load and call are not
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2665 supported). The following is the syntax for constant expressions:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2666
2667<dl>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2668 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2669 <dd>Truncate a constant to another type. The bit size of CST must be larger
2670 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2671
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2672 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2673 <dd>Zero extend a constant to another type. The bit size of CST must be
Duncan Sandsa522e562010-07-13 12:06:14 +0000[diff] [blame]2674 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2675
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2676 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2677 <dd>Sign extend a constant to another type. The bit size of CST must be
Duncan Sandsa522e562010-07-13 12:06:14 +0000[diff] [blame]2678 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2679
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2680 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2681 <dd>Truncate a floating point constant to another floating point type. The
2682 size of CST must be larger than the size of TYPE. Both types must be
2683 floating point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2684
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2685 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2686 <dd>Floating point extend a constant to another type. The size of CST must be
2687 smaller or equal to the size of TYPE. Both types must be floating
2688 point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2689
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2690 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2691 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2692 constant. TYPE must be a scalar or vector integer type. CST must be of
2693 scalar or vector floating point type. Both CST and TYPE must be scalars,
2694 or vectors of the same number of elements. If the value won't fit in the
2695 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2696
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2697 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2698 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2699 constant. TYPE must be a scalar or vector integer type. CST must be of
2700 scalar or vector floating point type. Both CST and TYPE must be scalars,
2701 or vectors of the same number of elements. If the value won't fit in the
2702 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2703
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2704 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2705 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2706 constant. TYPE must be a scalar or vector floating point type. CST must be
2707 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2708 vectors of the same number of elements. If the value won't fit in the
2709 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2710
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2711 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2712 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2713 constant. TYPE must be a scalar or vector floating point type. CST must be
2714 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2715 vectors of the same number of elements. If the value won't fit in the
2716 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2717
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2718 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2719 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2720 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2721 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2722 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2723
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2724 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2725 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2726 type. CST must be of integer type. The CST value is zero extended,
2727 truncated, or unchanged to make it fit in a pointer size. This one is
2728 <i>really</i> dangerous!</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2729
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2730 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner789dee32009-02-28 18:27:03 +0000[diff] [blame]2731 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2732 are the same as those for the <a href="#i_bitcast">bitcast
2733 instruction</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2734
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2735 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2736 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2737 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2738 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2739 instruction, the index list may have zero or more indexes, which are
2740 required to make sense for the type of "CSTPTR".</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2741
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2742 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2743 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2744
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2745 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2746 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2747
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2748 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2749 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2750
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2751 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2752 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2753 constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2754
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2755 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2756 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2757 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2758
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2759 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2760 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2761 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2762
Nick Lewycky9ab9a7f2010-05-29 06:44:15 +0000[diff] [blame]2763 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2764 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2765 constants. The index list is interpreted in a similar manner as indices in
2766 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2767 index value must be specified.</dd>
2768
2769 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2770 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2771 constants. The index list is interpreted in a similar manner as indices in
2772 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2773 index value must be specified.</dd>
2774
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2775 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2776 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2777 be any of the <a href="#binaryops">binary</a>
2778 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2779 on operands are the same as those for the corresponding instruction
2780 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2781</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2782
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2783</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]2784
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2785</div>
2786
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2787<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2788<h2><a name="othervalues">Other Values</a></h2>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2789<!-- *********************************************************************** -->
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2790<div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2791<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2792<h3>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2793<a name="inlineasm">Inline Assembler Expressions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2794</h3>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2795
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2796<div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2797
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2798<p>LLVM supports inline assembler expressions (as opposed
2799 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2800 a special value. This value represents the inline assembler as a string
2801 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2802 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2803 expression has side effects, and a flag indicating whether the function
2804 containing the asm needs to align its stack conservatively. An example
2805 inline assembler expression is:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2806
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2807<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2808i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2809</pre>
2810
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2811<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2812 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2813 have:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2814
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2815<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2816%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2817</pre>
2818
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2819<p>Inline asms with side effects not visible in the constraint list must be
2820 marked as having side effects. This is done through the use of the
2821 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2822
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2823<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2824call void asm sideeffect "eieio", ""()
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2825</pre>
2826
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2827<p>In some cases inline asms will contain code that will not work unless the
2828 stack is aligned in some way, such as calls or SSE instructions on x86,
2829 yet will not contain code that does that alignment within the asm.
2830 The compiler should make conservative assumptions about what the asm might
2831 contain and should generate its usual stack alignment code in the prologue
2832 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2833
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2834<pre class="doc_code">
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2835call void asm alignstack "eieio", ""()
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2836</pre>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2837
2838<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2839 first.</p>
2840
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2841<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2842 documented here. Constraints on what can be done (e.g. duplication, moving,
2843 etc need to be documented). This is probably best done by reference to
2844 another document that covers inline asm from a holistic perspective.</p>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2845
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2846<h4>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2847<a name="inlineasm_md">Inline Asm Metadata</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2848</h4>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2849
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2850<div>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2851
2852<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
Chris Lattner79ffdc72010-11-17 08:20:42 +0000[diff] [blame]2853 attached to it that contains a list of constant integers. If present, the
2854 code generator will use the integer as the location cookie value when report
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2855 errors through the LLVMContext error reporting mechanisms. This allows a
Dan Gohman61110ae2010-04-28 00:36:01 +0000[diff] [blame]2856 front-end to correlate backend errors that occur with inline asm back to the
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2857 source code that produced it. For example:</p>
2858
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2859<pre class="doc_code">
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2860call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2861...
2862!42 = !{ i32 1234567 }
2863</pre>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2864
2865<p>It is up to the front-end to make sense of the magic numbers it places in the
Chris Lattner79ffdc72010-11-17 08:20:42 +0000[diff] [blame]2866 IR. If the MDNode contains multiple constants, the code generator will use
2867 the one that corresponds to the line of the asm that the error occurs on.</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2868
2869</div>
2870
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2871</div>
2872
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2873<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2874<h3>
2875 <a name="metadata">Metadata Nodes and Metadata Strings</a>
2876</h3>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2877
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2878<div>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2879
2880<p>LLVM IR allows metadata to be attached to instructions in the program that
2881 can convey extra information about the code to the optimizers and code
2882 generator. One example application of metadata is source-level debug
2883 information. There are two metadata primitives: strings and nodes. All
2884 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2885 preceding exclamation point ('<tt>!</tt>').</p>
2886
2887<p>A metadata string is a string surrounded by double quotes. It can contain
2888 any character by escaping non-printable characters with "\xx" where "xx" is
2889 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2890
2891<p>Metadata nodes are represented with notation similar to structure constants
2892 (a comma separated list of elements, surrounded by braces and preceded by an
2893 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2894 10}</tt>". Metadata nodes can have any values as their operand.</p>
2895
2896<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2897 metadata nodes, which can be looked up in the module symbol table. For
2898 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2899
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2900<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2901 function is using two metadata arguments.</p>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2902
Bill Wendlingc0e10672011-03-02 02:17:11 +0000[diff] [blame]2903<div class="doc_code">
2904<pre>
2905call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2906</pre>
2907</div>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2908
2909<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2910 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.</p>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2911
Bill Wendlingc0e10672011-03-02 02:17:11 +0000[diff] [blame]2912<div class="doc_code">
2913<pre>
2914%indvar.next = add i64 %indvar, 1, !dbg !21
2915</pre>
2916</div>
2917
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2918</div>
2919
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2920</div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2921
2922<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2923<h2>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2924 <a name="intrinsic_globals">Intrinsic Global Variables</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2925</h2>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2926<!-- *********************************************************************** -->
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2927<div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2928<p>LLVM has a number of "magic" global variables that contain data that affect
2929code generation or other IR semantics. These are documented here. All globals
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2930of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2931section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2932by LLVM.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2933
2934<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2935<h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2936<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2937</h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2938
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2939<div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2940
2941<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2942href="#linkage_appending">appending linkage</a>. This array contains a list of
2943pointers to global variables and functions which may optionally have a pointer
2944cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2945
2946<pre>
2947 @X = global i8 4
2948 @Y = global i32 123
2949
2950 @llvm.used = appending global [2 x i8*] [
2951 i8* @X,
2952 i8* bitcast (i32* @Y to i8*)
2953 ], section "llvm.metadata"
2954</pre>
2955
2956<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2957compiler, assembler, and linker are required to treat the symbol as if there is
2958a reference to the global that it cannot see. For example, if a variable has
2959internal linkage and no references other than that from the <tt>@llvm.used</tt>
2960list, it cannot be deleted. This is commonly used to represent references from
2961inline asms and other things the compiler cannot "see", and corresponds to
2962"attribute((used))" in GNU C.</p>
2963
2964<p>On some targets, the code generator must emit a directive to the assembler or
2965object file to prevent the assembler and linker from molesting the symbol.</p>
2966
2967</div>
2968
2969<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2970<h3>
2971 <a name="intg_compiler_used">
2972 The '<tt>llvm.compiler.used</tt>' Global Variable
2973 </a>
2974</h3>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2975
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2976<div>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2977
2978<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2979<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2980touching the symbol. On targets that support it, this allows an intelligent
2981linker to optimize references to the symbol without being impeded as it would be
2982by <tt>@llvm.used</tt>.</p>
2983
2984<p>This is a rare construct that should only be used in rare circumstances, and
2985should not be exposed to source languages.</p>
2986
2987</div>
2988
2989<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2990<h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2991<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2992</h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2993
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2994<div>
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2995<pre>
2996%0 = type { i32, void ()* }
David Chisnallb492b812010-04-30 19:27:35 +0000[diff] [blame]2997@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2998</pre>
2999<p>The <tt>@llvm.global_ctors</tt> array contains a list of constructor functions and associated priorities. The functions referenced by this array will be called in ascending order of priority (i.e. lowest first) when the module is loaded. The order of functions with the same priority is not defined.
3000</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3001
3002</div>
3003
3004<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3005<h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3006<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3007</h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3008
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3009<div>
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]3010<pre>
3011%0 = type { i32, void ()* }
David Chisnallb492b812010-04-30 19:27:35 +0000[diff] [blame]3012@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]3013</pre>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3014
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]3015<p>The <tt>@llvm.global_dtors</tt> array contains a list of destructor functions and associated priorities. The functions referenced by this array will be called in descending order of priority (i.e. highest first) when the module is loaded. The order of functions with the same priority is not defined.
3016</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3017
3018</div>
3019
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3020</div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3021
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]3022<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3023<h2><a name="instref">Instruction Reference</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3024<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3025
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3026<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3027
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3028<p>The LLVM instruction set consists of several different classifications of
3029 instructions: <a href="#terminators">terminator
3030 instructions</a>, <a href="#binaryops">binary instructions</a>,
3031 <a href="#bitwiseops">bitwise binary instructions</a>,
3032 <a href="#memoryops">memory instructions</a>, and
3033 <a href="#otherops">other instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3034
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3035<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3036<h3>
3037 <a name="terminators">Terminator Instructions</a>
3038</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3039
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3040<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3041
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3042<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
3043 in a program ends with a "Terminator" instruction, which indicates which
3044 block should be executed after the current block is finished. These
3045 terminator instructions typically yield a '<tt>void</tt>' value: they produce
3046 control flow, not values (the one exception being the
3047 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
3048
Chris Lattnerd3d65ab2011-08-02 20:29:13 +0000[diff] [blame]3049<p>The terminator instructions are:
3050 '<a href="#i_ret"><tt>ret</tt></a>',
3051 '<a href="#i_br"><tt>br</tt></a>',
3052 '<a href="#i_switch"><tt>switch</tt></a>',
3053 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>',
3054 '<a href="#i_invoke"><tt>invoke</tt></a>',
3055 '<a href="#i_unwind"><tt>unwind</tt></a>',
3056 '<a href="#i_resume"><tt>resume</tt></a>', and
3057 '<a href="#i_unreachable"><tt>unreachable</tt></a>'.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3058
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3059<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3060<h4>
3061 <a name="i_ret">'<tt>ret</tt>' Instruction</a>
3062</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3063
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3064<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3065
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3066<h5>Syntax:</h5>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]3067<pre>
3068 ret &lt;type&gt; &lt;value&gt; <i>; Return a value from a non-void function</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]3069 ret void <i>; Return from void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3070</pre>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3071
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3072<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3073<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
3074 a value) from a function back to the caller.</p>
3075
3076<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
3077 value and then causes control flow, and one that just causes control flow to
3078 occur.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3079
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3080<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3081<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
3082 return value. The type of the return value must be a
3083 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]3084
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3085<p>A function is not <a href="#wellformed">well formed</a> if it it has a
3086 non-void return type and contains a '<tt>ret</tt>' instruction with no return
3087 value or a return value with a type that does not match its type, or if it
3088 has a void return type and contains a '<tt>ret</tt>' instruction with a
3089 return value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3090
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3091<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3092<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
3093 the calling function's context. If the caller is a
3094 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
3095 instruction after the call. If the caller was an
3096 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
3097 the beginning of the "normal" destination block. If the instruction returns
3098 a value, that value shall set the call or invoke instruction's return
3099 value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3100
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3101<h5>Example:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3102<pre>
3103 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]3104 ret void <i>; Return from a void function</i>
Bill Wendling050ee8f2009-02-28 22:12:54 +0000[diff] [blame]3105 ret { i32, i8 } { i32 4, i8 2 } <i>; Return a struct of values 4 and 2</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3106</pre>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]3107
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3108</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3109<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3110<h4>
3111 <a name="i_br">'<tt>br</tt>' Instruction</a>
3112</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3113
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3114<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3115
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3116<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3117<pre>
Bill Wendling16b86742011-07-26 10:41:15 +0000[diff] [blame]3118 br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;
3119 br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3120</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3121
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3122<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3123<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
3124 different basic block in the current function. There are two forms of this
3125 instruction, corresponding to a conditional branch and an unconditional
3126 branch.</p>
3127
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3128<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3129<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
3130 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
3131 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
3132 target.</p>
3133
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3134<h5>Semantics:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3135<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3136 argument is evaluated. If the value is <tt>true</tt>, control flows to the
3137 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
3138 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
3139
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3140<h5>Example:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]3141<pre>
3142Test:
3143 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
3144 br i1 %cond, label %IfEqual, label %IfUnequal
3145IfEqual:
3146 <a href="#i_ret">ret</a> i32 1
3147IfUnequal:
3148 <a href="#i_ret">ret</a> i32 0
3149</pre>
3150
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3151</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3152
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3153<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3154<h4>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3155 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3156</h4>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3157
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3158<div>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3159
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3160<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3161<pre>
3162 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
3163</pre>
3164
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3165<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3166<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3167 several different places. It is a generalization of the '<tt>br</tt>'
3168 instruction, allowing a branch to occur to one of many possible
3169 destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3170
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3171<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3172<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3173 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
3174 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
3175 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3176
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3177<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3178<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3179 destinations. When the '<tt>switch</tt>' instruction is executed, this table
3180 is searched for the given value. If the value is found, control flow is
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]3181 transferred to the corresponding destination; otherwise, control flow is
3182 transferred to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3183
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3184<h5>Implementation:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3185<p>Depending on properties of the target machine and the particular
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3186 <tt>switch</tt> instruction, this instruction may be code generated in
3187 different ways. For example, it could be generated as a series of chained
3188 conditional branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3189
3190<h5>Example:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3191<pre>
3192 <i>; Emulate a conditional br instruction</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3193 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]3194 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3195
3196 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3197 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3198
3199 <i>; Implement a jump table:</i>
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]3200 switch i32 %val, label %otherwise [ i32 0, label %onzero
3201 i32 1, label %onone
3202 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3203</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3204
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3205</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3206
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3207
3208<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3209<h4>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3210 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3211</h4>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3212
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3213<div>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3214
3215<h5>Syntax:</h5>
3216<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3217 indirectbr &lt;somety&gt;* &lt;address&gt;, [ label &lt;dest1&gt;, label &lt;dest2&gt;, ... ]
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3218</pre>
3219
3220<h5>Overview:</h5>
3221
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3222<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3223 within the current function, whose address is specified by
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]3224 "<tt>address</tt>". Address must be derived from a <a
3225 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3226
3227<h5>Arguments:</h5>
3228
3229<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3230 rest of the arguments indicate the full set of possible destinations that the
3231 address may point to. Blocks are allowed to occur multiple times in the
3232 destination list, though this isn't particularly useful.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3233
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3234<p>This destination list is required so that dataflow analysis has an accurate
3235 understanding of the CFG.</p>
3236
3237<h5>Semantics:</h5>
3238
3239<p>Control transfers to the block specified in the address argument. All
3240 possible destination blocks must be listed in the label list, otherwise this
3241 instruction has undefined behavior. This implies that jumps to labels
3242 defined in other functions have undefined behavior as well.</p>
3243
3244<h5>Implementation:</h5>
3245
3246<p>This is typically implemented with a jump through a register.</p>
3247
3248<h5>Example:</h5>
3249<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3250 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3251</pre>
3252
3253</div>
3254
3255
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3256<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3257<h4>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3258 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3259</h4>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3260
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3261<div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3262
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3263<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3264<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3265 &lt;result&gt; = invoke [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>] &lt;ptr to function ty&gt; &lt;function ptr val&gt;(&lt;function args&gt;) [<a href="#fnattrs">fn attrs</a>]
Chris Lattner6b7a0082006-05-14 18:23:06 +0000[diff] [blame]3266 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3267</pre>
3268
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3269<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3270<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3271 function, with the possibility of control flow transfer to either the
3272 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3273 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3274 control flow will return to the "normal" label. If the callee (or any
3275 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3276 instruction, control is interrupted and continued at the dynamically nearest
3277 "exception" label.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3278
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3279<p>The '<tt>exception</tt>' label is a
3280 <i><a href="ExceptionHandling.html#overview">landing pad</a></i> for the
3281 exception. As such, '<tt>exception</tt>' label is required to have the
3282 "<a href="#i_landingpad"><tt>landingpad</tt></a>" instruction, which contains
3283 the information about about the behavior of the program after unwinding
3284 happens, as its first non-PHI instruction. The restrictions on the
3285 "<tt>landingpad</tt>" instruction's tightly couples it to the
3286 "<tt>invoke</tt>" instruction, so that the important information contained
3287 within the "<tt>landingpad</tt>" instruction can't be lost through normal
3288 code motion.</p>
3289
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3290<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3291<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3292
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3293<ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3294 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3295 convention</a> the call should use. If none is specified, the call
3296 defaults to using C calling conventions.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3297
3298 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3299 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3300 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3301
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3302 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3303 function value being invoked. In most cases, this is a direct function
3304 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3305 off an arbitrary pointer to function value.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3306
3307 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3308 function to be invoked. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3309
3310 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]3311 signature argument types and parameter attributes. All arguments must be
3312 of <a href="#t_firstclass">first class</a> type. If the function
3313 signature indicates the function accepts a variable number of arguments,
3314 the extra arguments can be specified.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3315
3316 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3317 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3318
3319 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3320 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3321
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3322 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3323 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3324 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3325</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3326
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3327<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3328<p>This instruction is designed to operate as a standard
3329 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3330 primary difference is that it establishes an association with a label, which
3331 is used by the runtime library to unwind the stack.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3332
3333<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3334 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3335 exception. Additionally, this is important for implementation of
3336 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3337
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3338<p>For the purposes of the SSA form, the definition of the value returned by the
3339 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3340 block to the "normal" label. If the callee unwinds then no return value is
3341 available.</p>
Dan Gohman9069d892009-05-22 21:47:08 +0000[diff] [blame]3342
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]3343<p>Note that the code generator does not yet completely support unwind, and
3344that the invoke/unwind semantics are likely to change in future versions.</p>
3345
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3346<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3347<pre>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3348 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3349 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3350 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3351 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3352</pre>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3353
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3354</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3355
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3356<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3357
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3358<h4>
3359 <a name="i_unwind">'<tt>unwind</tt>' Instruction</a>
3360</h4>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3361
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3362<div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3363
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3364<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3365<pre>
3366 unwind
3367</pre>
3368
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3369<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3370<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3371 at the first callee in the dynamic call stack which used
3372 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3373 This is primarily used to implement exception handling.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3374
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3375<h5>Semantics:</h5>
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]3376<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3377 immediately halt. The dynamic call stack is then searched for the
3378 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3379 Once found, execution continues at the "exceptional" destination block
3380 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3381 instruction in the dynamic call chain, undefined behavior results.</p>
3382
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]3383<p>Note that the code generator does not yet completely support unwind, and
3384that the invoke/unwind semantics are likely to change in future versions.</p>
3385
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3386</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3387
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]3388 <!-- _______________________________________________________________________ -->
3389
3390<h4>
3391 <a name="i_resume">'<tt>resume</tt>' Instruction</a>
3392</h4>
3393
3394<div>
3395
3396<h5>Syntax:</h5>
3397<pre>
3398 resume &lt;type&gt; &lt;value&gt;
3399</pre>
3400
3401<h5>Overview:</h5>
3402<p>The '<tt>resume</tt>' instruction is a terminator instruction that has no
3403 successors.</p>
3404
3405<h5>Arguments:</h5>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3406<p>The '<tt>resume</tt>' instruction requires one argument, which must have the
Bill Wendlingc5a13612011-08-03 18:37:32 +0000[diff] [blame]3407 same type as the result of any '<tt>landingpad</tt>' instruction in the same
3408 function.</p>
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]3409
3410<h5>Semantics:</h5>
3411<p>The '<tt>resume</tt>' instruction resumes propagation of an existing
3412 (in-flight) exception whose unwinding was interrupted with
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3413 a <a href="#i_landingpad"><tt>landingpad</tt></a> instruction.</p>
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]3414
3415<h5>Example:</h5>
3416<pre>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3417 resume { i8*, i32 } %exn
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]3418</pre>
3419
3420</div>
3421
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3422<!-- _______________________________________________________________________ -->
3423
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3424<h4>
3425 <a name="i_unreachable">'<tt>unreachable</tt>' Instruction</a>
3426</h4>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3427
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3428<div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3429
3430<h5>Syntax:</h5>
3431<pre>
3432 unreachable
3433</pre>
3434
3435<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3436<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3437 instruction is used to inform the optimizer that a particular portion of the
3438 code is not reachable. This can be used to indicate that the code after a
3439 no-return function cannot be reached, and other facts.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3440
3441<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3442<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3443
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3444</div>
3445
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3446</div>
3447
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3448<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3449<h3>
3450 <a name="binaryops">Binary Operations</a>
3451</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3452
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3453<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3454
3455<p>Binary operators are used to do most of the computation in a program. They
3456 require two operands of the same type, execute an operation on them, and
3457 produce a single value. The operands might represent multiple data, as is
3458 the case with the <a href="#t_vector">vector</a> data type. The result value
3459 has the same type as its operands.</p>
3460
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3461<p>There are several different binary operators:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3462
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3463<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3464<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3465 <a name="i_add">'<tt>add</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3466</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3467
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3468<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3469
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3470<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3471<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3472 &lt;result&gt; = add &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohman957b1312009-09-02 17:31:42 +0000[diff] [blame]3473 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3474 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3475 &lt;result&gt; = add nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3476</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3477
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3478<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3479<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3480
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3481<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3482<p>The two arguments to the '<tt>add</tt>' instruction must
3483 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3484 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3485
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3486<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3487<p>The value produced is the integer sum of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3488
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3489<p>If the sum has unsigned overflow, the result returned is the mathematical
3490 result modulo 2<sup>n</sup>, where n is the bit width of the result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3491
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3492<p>Because LLVM integers use a two's complement representation, this instruction
3493 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3494
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3495<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3496 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3497 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3498 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3499 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3500
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3501<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3502<pre>
3503 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3504</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3505
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3506</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3507
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3508<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3509<h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3510 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3511</h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3512
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3513<div>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3514
3515<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3516<pre>
3517 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3518</pre>
3519
3520<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3521<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3522
3523<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3524<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3525 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3526 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3527
3528<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3529<p>The value produced is the floating point sum of the two operands.</p>
3530
3531<h5>Example:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3532<pre>
3533 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3534</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3535
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3536</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3537
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3538<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3539<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3540 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3541</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3542
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3543<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3544
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3545<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3546<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3547 &lt;result&gt; = sub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohman957b1312009-09-02 17:31:42 +0000[diff] [blame]3548 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3549 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3550 &lt;result&gt; = sub nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3551</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3552
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3553<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3554<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3555 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3556
3557<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3558 '<tt>neg</tt>' instruction present in most other intermediate
3559 representations.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3560
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3561<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3562<p>The two arguments to the '<tt>sub</tt>' instruction must
3563 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3564 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3565
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3566<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3567<p>The value produced is the integer difference of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3568
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3569<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3570 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3571 result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3572
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3573<p>Because LLVM integers use a two's complement representation, this instruction
3574 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3575
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3576<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3577 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3578 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3579 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3580 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3581
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3582<h5>Example:</h5>
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]3583<pre>
3584 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3585 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3586</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3587
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3588</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3589
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3590<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3591<h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3592 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3593</h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3594
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3595<div>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3596
3597<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3598<pre>
3599 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3600</pre>
3601
3602<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3603<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3604 operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3605
3606<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3607 '<tt>fneg</tt>' instruction present in most other intermediate
3608 representations.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3609
3610<h5>Arguments:</h5>
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]3611<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3612 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3613 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3614
3615<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3616<p>The value produced is the floating point difference of the two operands.</p>
3617
3618<h5>Example:</h5>
3619<pre>
3620 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3621 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3622</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3623
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3624</div>
3625
3626<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3627<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3628 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3629</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3630
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3631<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3632
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3633<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3634<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3635 &lt;result&gt; = mul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohman957b1312009-09-02 17:31:42 +0000[diff] [blame]3636 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3637 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3638 &lt;result&gt; = mul nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3639</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3640
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3641<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3642<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3643
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3644<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3645<p>The two arguments to the '<tt>mul</tt>' instruction must
3646 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3647 integer values. Both arguments must have identical types.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3648
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3649<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3650<p>The value produced is the integer product of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3651
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3652<p>If the result of the multiplication has unsigned overflow, the result
3653 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3654 width of the result.</p>
3655
3656<p>Because LLVM integers use a two's complement representation, and the result
3657 is the same width as the operands, this instruction returns the correct
3658 result for both signed and unsigned integers. If a full product
3659 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3660 be sign-extended or zero-extended as appropriate to the width of the full
3661 product.</p>
3662
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3663<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3664 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3665 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3666 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3667 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3668
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3669<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3670<pre>
3671 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3672</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3673
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3674</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3675
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3676<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3677<h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3678 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3679</h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3680
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3681<div>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3682
3683<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3684<pre>
3685 &lt;result&gt; = fmul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3686</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3687
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3688<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3689<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3690
3691<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3692<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3693 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3694 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3695
3696<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3697<p>The value produced is the floating point product of the two operands.</p>
3698
3699<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3700<pre>
3701 &lt;result&gt; = fmul float 4.0, %var <i>; yields {float}:result = 4.0 * %var</i>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3702</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3703
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3704</div>
3705
3706<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3707<h4>
3708 <a name="i_udiv">'<tt>udiv</tt>' Instruction</a>
3709</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3710
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3711<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3712
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3713<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3714<pre>
Chris Lattner35315d02011-02-06 21:44:57 +0000[diff] [blame]3715 &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3716 &lt;result&gt; = udiv exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3717</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3718
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3719<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3720<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3721
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3722<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3723<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3724 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3725 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3726
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3727<h5>Semantics:</h5>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3728<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3729
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3730<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3731 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3732
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3733<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3734
Chris Lattner35315d02011-02-06 21:44:57 +0000[diff] [blame]3735<p>If the <tt>exact</tt> keyword is present, the result value of the
3736 <tt>udiv</tt> is a <a href="#trapvalues">trap value</a> if %op1 is not a
3737 multiple of %op2 (as such, "((a udiv exact b) mul b) == a").</p>
3738
3739
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3740<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3741<pre>
3742 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3743</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3744
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3745</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3746
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3747<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3748<h4>
3749 <a name="i_sdiv">'<tt>sdiv</tt>' Instruction</a>
3750</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3751
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3752<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3753
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3754<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3755<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3756 &lt;result&gt; = sdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohman957b1312009-09-02 17:31:42 +0000[diff] [blame]3757 &lt;result&gt; = sdiv exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3758</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3759
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3760<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3761<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3762
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3763<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3764<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3765 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3766 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3767
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3768<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3769<p>The value produced is the signed integer quotient of the two operands rounded
3770 towards zero.</p>
3771
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3772<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3773 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3774
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3775<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3776 undefined behavior; this is a rare case, but can occur, for example, by doing
3777 a 32-bit division of -2147483648 by -1.</p>
3778
Dan Gohman71dfd782009-07-22 00:04:19 +0000[diff] [blame]3779<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]3780 <tt>sdiv</tt> is a <a href="#trapvalues">trap value</a> if the result would
Dan Gohmane501ff72010-07-11 00:08:34 +0000[diff] [blame]3781 be rounded.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3782
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3783<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3784<pre>
3785 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3786</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3787
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3788</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3789
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3790<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3791<h4>
3792 <a name="i_fdiv">'<tt>fdiv</tt>' Instruction</a>
3793</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3794
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3795<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3796
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3797<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3798<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3799 &lt;result&gt; = fdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3800</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3801
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3802<h5>Overview:</h5>
3803<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3804
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3805<h5>Arguments:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3806<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3807 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3808 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3809
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3810<h5>Semantics:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3811<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3812
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3813<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3814<pre>
3815 &lt;result&gt; = fdiv float 4.0, %var <i>; yields {float}:result = 4.0 / %var</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3816</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3817
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3818</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3819
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3820<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3821<h4>
3822 <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3823</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3824
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3825<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3826
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3827<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3828<pre>
3829 &lt;result&gt; = urem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3830</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3831
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3832<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3833<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3834 division of its two arguments.</p>
3835
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3836<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3837<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3838 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3839 values. Both arguments must have identical types.</p>
3840
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3841<h5>Semantics:</h5>
3842<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3843 This instruction always performs an unsigned division to get the
3844 remainder.</p>
3845
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3846<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3847 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3848
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3849<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3850
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3851<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3852<pre>
3853 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3854</pre>
3855
3856</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3857
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3858<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3859<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3860 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3861</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3862
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3863<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3864
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3865<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3866<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3867 &lt;result&gt; = srem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3868</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3869
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3870<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3871<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3872 division of its two operands. This instruction can also take
3873 <a href="#t_vector">vector</a> versions of the values in which case the
3874 elements must be integers.</p>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]3875
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3876<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3877<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3878 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3879 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3880
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3881<h5>Semantics:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3882<p>This instruction returns the <i>remainder</i> of a division (where the result
Duncan Sands2769c6e2011-03-07 09:12:24 +0000[diff] [blame]3883 is either zero or has the same sign as the dividend, <tt>op1</tt>), not the
3884 <i>modulo</i> operator (where the result is either zero or has the same sign
3885 as the divisor, <tt>op2</tt>) of a value.
3886 For more information about the difference,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3887 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3888 Math Forum</a>. For a table of how this is implemented in various languages,
3889 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3890 Wikipedia: modulo operation</a>.</p>
3891
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3892<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3893 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3894
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3895<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3896 Overflow also leads to undefined behavior; this is a rare case, but can
3897 occur, for example, by taking the remainder of a 32-bit division of
3898 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3899 lets srem be implemented using instructions that return both the result of
3900 the division and the remainder.)</p>
3901
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3902<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3903<pre>
3904 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3905</pre>
3906
3907</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3908
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3909<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3910<h4>
3911 <a name="i_frem">'<tt>frem</tt>' Instruction</a>
3912</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3913
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3914<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3915
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3916<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3917<pre>
3918 &lt;result&gt; = frem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3919</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3920
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3921<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3922<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3923 its two operands.</p>
3924
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3925<h5>Arguments:</h5>
3926<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3927 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3928 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3929
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3930<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3931<p>This instruction returns the <i>remainder</i> of a division. The remainder
3932 has the same sign as the dividend.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3933
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3934<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3935<pre>
3936 &lt;result&gt; = frem float 4.0, %var <i>; yields {float}:result = 4.0 % %var</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3937</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3938
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3939</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]3940
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3941</div>
3942
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3943<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3944<h3>
3945 <a name="bitwiseops">Bitwise Binary Operations</a>
3946</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3947
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3948<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3949
3950<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3951 program. They are generally very efficient instructions and can commonly be
3952 strength reduced from other instructions. They require two operands of the
3953 same type, execute an operation on them, and produce a single value. The
3954 resulting value is the same type as its operands.</p>
3955
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3956<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3957<h4>
3958 <a name="i_shl">'<tt>shl</tt>' Instruction</a>
3959</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3960
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3961<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3962
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3963<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3964<pre>
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]3965 &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3966 &lt;result&gt; = shl nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3967 &lt;result&gt; = shl nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3968 &lt;result&gt; = shl nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3969</pre>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3970
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3971<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3972<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3973 a specified number of bits.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3974
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3975<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3976<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3977 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3978 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3979
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3980<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3981<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3982 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3983 is (statically or dynamically) negative or equal to or larger than the number
3984 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3985 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3986 shift amount in <tt>op2</tt>.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3987
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]3988<p>If the <tt>nuw</tt> keyword is present, then the shift produces a
3989 <a href="#trapvalues">trap value</a> if it shifts out any non-zero bits. If
Chris Lattnerf10dfdc2011-02-09 16:44:44 +0000[diff] [blame]3990 the <tt>nsw</tt> keyword is present, then the shift produces a
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]3991 <a href="#trapvalues">trap value</a> if it shifts out any bits that disagree
3992 with the resultant sign bit. As such, NUW/NSW have the same semantics as
3993 they would if the shift were expressed as a mul instruction with the same
3994 nsw/nuw bits in (mul %op1, (shl 1, %op2)).</p>
3995
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3996<h5>Example:</h5>
3997<pre>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3998 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3999 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
4000 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4001 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]4002 &lt;result&gt; = shl &lt;2 x i32&gt; &lt; i32 1, i32 1&gt;, &lt; i32 1, i32 2&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 2, i32 4&gt;</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4003</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4004
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4005</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4006
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4007<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4008<h4>
4009 <a name="i_lshr">'<tt>lshr</tt>' Instruction</a>
4010</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4011
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4012<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4013
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4014<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4015<pre>
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4016 &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4017 &lt;result&gt; = lshr exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4018</pre>
4019
4020<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4021<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
4022 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4023
4024<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4025<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4026 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4027 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4028
4029<h5>Semantics:</h5>
4030<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4031 significant bits of the result will be filled with zero bits after the shift.
4032 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
4033 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4034 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4035 shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4036
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4037<p>If the <tt>exact</tt> keyword is present, the result value of the
4038 <tt>lshr</tt> is a <a href="#trapvalues">trap value</a> if any of the bits
4039 shifted out are non-zero.</p>
4040
4041
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4042<h5>Example:</h5>
4043<pre>
4044 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
4045 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
4046 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
4047 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4048 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]4049 &lt;result&gt; = lshr &lt;2 x i32&gt; &lt; i32 -2, i32 4&gt;, &lt; i32 1, i32 2&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 0x7FFFFFFF, i32 1&gt;</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4050</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4051
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4052</div>
4053
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]4054<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4055<h4>
4056 <a name="i_ashr">'<tt>ashr</tt>' Instruction</a>
4057</h4>
4058
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4059<div>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4060
4061<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4062<pre>
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4063 &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4064 &lt;result&gt; = ashr exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4065</pre>
4066
4067<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4068<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
4069 operand shifted to the right a specified number of bits with sign
4070 extension.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4071
4072<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4073<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4074 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4075 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4076
4077<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4078<p>This instruction always performs an arithmetic shift right operation, The
4079 most significant bits of the result will be filled with the sign bit
4080 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
4081 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
4082 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
4083 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4084
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4085<p>If the <tt>exact</tt> keyword is present, the result value of the
4086 <tt>ashr</tt> is a <a href="#trapvalues">trap value</a> if any of the bits
4087 shifted out are non-zero.</p>
4088
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4089<h5>Example:</h5>
4090<pre>
4091 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
4092 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
4093 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
4094 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4095 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]4096 &lt;result&gt; = ashr &lt;2 x i32&gt; &lt; i32 -2, i32 4&gt;, &lt; i32 1, i32 3&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 -1, i32 0&gt;</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4097</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4098
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4099</div>
4100
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4101<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4102<h4>
4103 <a name="i_and">'<tt>and</tt>' Instruction</a>
4104</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4105
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4106<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4107
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4108<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4109<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]4110 &lt;result&gt; = and &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4111</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4112
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4113<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4114<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
4115 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4116
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4117<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4118<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4119 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4120 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4121
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4122<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4123<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4124
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4125<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4126 <tbody>
4127 <tr>
4128 <td>In0</td>
4129 <td>In1</td>
4130 <td>Out</td>
4131 </tr>
4132 <tr>
4133 <td>0</td>
4134 <td>0</td>
4135 <td>0</td>
4136 </tr>
4137 <tr>
4138 <td>0</td>
4139 <td>1</td>
4140 <td>0</td>
4141 </tr>
4142 <tr>
4143 <td>1</td>
4144 <td>0</td>
4145 <td>0</td>
4146 </tr>
4147 <tr>
4148 <td>1</td>
4149 <td>1</td>
4150 <td>1</td>
4151 </tr>
4152 </tbody>
4153</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4154
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4155<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4156<pre>
4157 &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4158 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
4159 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4160</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4161</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4162<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4163<h4>
4164 <a name="i_or">'<tt>or</tt>' Instruction</a>
4165</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4166
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4167<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4168
4169<h5>Syntax:</h5>
4170<pre>
4171 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4172</pre>
4173
4174<h5>Overview:</h5>
4175<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
4176 two operands.</p>
4177
4178<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4179<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4180 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4181 values. Both arguments must have identical types.</p>
4182
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4183<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4184<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4185
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4186<table border="1" cellspacing="0" cellpadding="4">
4187 <tbody>
4188 <tr>
4189 <td>In0</td>
4190 <td>In1</td>
4191 <td>Out</td>
4192 </tr>
4193 <tr>
4194 <td>0</td>
4195 <td>0</td>
4196 <td>0</td>
4197 </tr>
4198 <tr>
4199 <td>0</td>
4200 <td>1</td>
4201 <td>1</td>
4202 </tr>
4203 <tr>
4204 <td>1</td>
4205 <td>0</td>
4206 <td>1</td>
4207 </tr>
4208 <tr>
4209 <td>1</td>
4210 <td>1</td>
4211 <td>1</td>
4212 </tr>
4213 </tbody>
4214</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4215
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4216<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4217<pre>
4218 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4219 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
4220 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4221</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4222
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4223</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4224
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4225<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4226<h4>
4227 <a name="i_xor">'<tt>xor</tt>' Instruction</a>
4228</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4229
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4230<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4231
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4232<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4233<pre>
4234 &lt;result&gt; = xor &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4235</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4236
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4237<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4238<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
4239 its two operands. The <tt>xor</tt> is used to implement the "one's
4240 complement" operation, which is the "~" operator in C.</p>
4241
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4242<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4243<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4244 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4245 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4246
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4247<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4248<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4249
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4250<table border="1" cellspacing="0" cellpadding="4">
4251 <tbody>
4252 <tr>
4253 <td>In0</td>
4254 <td>In1</td>
4255 <td>Out</td>
4256 </tr>
4257 <tr>
4258 <td>0</td>
4259 <td>0</td>
4260 <td>0</td>
4261 </tr>
4262 <tr>
4263 <td>0</td>
4264 <td>1</td>
4265 <td>1</td>
4266 </tr>
4267 <tr>
4268 <td>1</td>
4269 <td>0</td>
4270 <td>1</td>
4271 </tr>
4272 <tr>
4273 <td>1</td>
4274 <td>1</td>
4275 <td>0</td>
4276 </tr>
4277 </tbody>
4278</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4279
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4280<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4281<pre>
4282 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4283 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
4284 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
4285 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4286</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4287
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4288</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4289
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4290</div>
4291
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4292<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4293<h3>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4294 <a name="vectorops">Vector Operations</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4295</h3>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4296
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4297<div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4298
4299<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4300 target-independent manner. These instructions cover the element-access and
4301 vector-specific operations needed to process vectors effectively. While LLVM
4302 does directly support these vector operations, many sophisticated algorithms
4303 will want to use target-specific intrinsics to take full advantage of a
4304 specific target.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4305
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4306<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4307<h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4308 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4309</h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4310
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4311<div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4312
4313<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4314<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4315 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4316</pre>
4317
4318<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4319<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4320 from a vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4321
4322
4323<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4324<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4325 of <a href="#t_vector">vector</a> type. The second operand is an index
4326 indicating the position from which to extract the element. The index may be
4327 a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4328
4329<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4330<p>The result is a scalar of the same type as the element type of
4331 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4332 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4333 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4334
4335<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4336<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4337 &lt;result&gt; = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4338</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4339
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4340</div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4341
4342<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4343<h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4344 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4345</h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4346
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4347<div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4348
4349<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4350<pre>
Dan Gohman43ba0672008-05-12 23:38:42 +0000[diff] [blame]4351 &lt;result&gt; = insertelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, &lt;ty&gt; &lt;elt&gt;, i32 &lt;idx&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4352</pre>
4353
4354<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4355<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4356 vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4357
4358<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4359<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4360 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4361 whose type must equal the element type of the first operand. The third
4362 operand is an index indicating the position at which to insert the value.
4363 The index may be a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4364
4365<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4366<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4367 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4368 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4369 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4370
4371<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4372<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4373 &lt;result&gt; = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4374</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4375
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4376</div>
4377
4378<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4379<h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4380 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4381</h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4382
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4383<div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4384
4385<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4386<pre>
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]4387 &lt;result&gt; = shufflevector &lt;n x &lt;ty&gt;&gt; &lt;v1&gt;, &lt;n x &lt;ty&gt;&gt; &lt;v2&gt;, &lt;m x i32&gt; &lt;mask&gt; <i>; yields &lt;m x &lt;ty&gt;&gt;</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4388</pre>
4389
4390<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4391<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4392 from two input vectors, returning a vector with the same element type as the
4393 input and length that is the same as the shuffle mask.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4394
4395<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4396<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4397 with types that match each other. The third argument is a shuffle mask whose
4398 element type is always 'i32'. The result of the instruction is a vector
4399 whose length is the same as the shuffle mask and whose element type is the
4400 same as the element type of the first two operands.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4401
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4402<p>The shuffle mask operand is required to be a constant vector with either
4403 constant integer or undef values.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4404
4405<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4406<p>The elements of the two input vectors are numbered from left to right across
4407 both of the vectors. The shuffle mask operand specifies, for each element of
4408 the result vector, which element of the two input vectors the result element
4409 gets. The element selector may be undef (meaning "don't care") and the
4410 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4411
4412<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4413<pre>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4414 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4415 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4416 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4417 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i> - Identity shuffle.
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4418 &lt;result&gt; = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]4419 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4420 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]4421 &lt;8 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7 &gt; <i>; yields &lt;8 x i32&gt;</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4422</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4423
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4424</div>
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]4425
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4426</div>
4427
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4428<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4429<h3>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4430 <a name="aggregateops">Aggregate Operations</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4431</h3>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4432
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4433<div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4434
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4435<p>LLVM supports several instructions for working with
4436 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4437
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4438<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4439<h4>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4440 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4441</h4>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4442
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4443<div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4444
4445<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4446<pre>
4447 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4448</pre>
4449
4450<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4451<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4452 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4453
4454<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4455<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]4456 of <a href="#t_struct">struct</a> or
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4457 <a href="#t_array">array</a> type. The operands are constant indices to
4458 specify which value to extract in a similar manner as indices in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4459 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Frits van Bommel7cf63ac2010-12-05 20:54:38 +0000[diff] [blame]4460 <p>The major differences to <tt>getelementptr</tt> indexing are:</p>
4461 <ul>
4462 <li>Since the value being indexed is not a pointer, the first index is
4463 omitted and assumed to be zero.</li>
4464 <li>At least one index must be specified.</li>
4465 <li>Not only struct indices but also array indices must be in
4466 bounds.</li>
4467 </ul>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4468
4469<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4470<p>The result is the value at the position in the aggregate specified by the
4471 index operands.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4472
4473<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4474<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4475 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4476</pre>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4477
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4478</div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4479
4480<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4481<h4>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4482 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4483</h4>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4484
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4485<div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4486
4487<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4488<pre>
Bill Wendlingf6a91cf2011-07-26 20:42:28 +0000[diff] [blame]4489 &lt;result&gt; = insertvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;ty&gt; &lt;elt&gt;, &lt;idx&gt;{, &lt;idx&gt;}* <i>; yields &lt;aggregate type&gt;</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4490</pre>
4491
4492<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4493<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4494 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4495
4496<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4497<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]4498 of <a href="#t_struct">struct</a> or
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4499 <a href="#t_array">array</a> type. The second operand is a first-class
4500 value to insert. The following operands are constant indices indicating
4501 the position at which to insert the value in a similar manner as indices in a
Frits van Bommel7cf63ac2010-12-05 20:54:38 +0000[diff] [blame]4502 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' instruction. The
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4503 value to insert must have the same type as the value identified by the
4504 indices.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4505
4506<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4507<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4508 that of <tt>val</tt> except that the value at the position specified by the
4509 indices is that of <tt>elt</tt>.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4510
4511<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4512<pre>
Chris Lattnerc2e85402011-05-22 07:18:08 +0000[diff] [blame]4513 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4514 %agg2 = insertvalue {i32, float} %agg1, float %val, 1 <i>; yields {i32 1, float %val}</i>
4515 %agg3 = insertvalue {i32, {float}} %agg1, float %val, 1, 0 <i>; yields {i32 1, float %val}</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4516</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4517
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4518</div>
4519
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4520</div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4521
4522<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4523<h3>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4524 <a name="memoryops">Memory Access and Addressing Operations</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4525</h3>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4526
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4527<div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4528
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4529<p>A key design point of an SSA-based representation is how it represents
4530 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]4531 very simple. This section describes how to read, write, and allocate
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4532 memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4533
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4534<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4535<h4>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4536 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4537</h4>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4538
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4539<div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4540
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4541<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4542<pre>
Dan Gohman2140a742010-05-28 01:14:11 +0000[diff] [blame]4543 &lt;result&gt; = alloca &lt;type&gt;[, &lt;ty&gt; &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4544</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4545
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4546<h5>Overview:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4547<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4548 currently executing function, to be automatically released when this function
4549 returns to its caller. The object is always allocated in the generic address
4550 space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4551
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4552<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4553<p>The '<tt>alloca</tt>' instruction
4554 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4555 runtime stack, returning a pointer of the appropriate type to the program.
4556 If "NumElements" is specified, it is the number of elements allocated,
4557 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4558 specified, the value result of the allocation is guaranteed to be aligned to
4559 at least that boundary. If not specified, or if zero, the target can choose
4560 to align the allocation on any convenient boundary compatible with the
4561 type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4562
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4563<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4564
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4565<h5>Semantics:</h5>
Bill Wendling9ee6a312009-05-08 20:49:29 +0000[diff] [blame]4566<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4567 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4568 memory is automatically released when the function returns. The
4569 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4570 variables that must have an address available. When the function returns
4571 (either with the <tt><a href="#i_ret">ret</a></tt>
4572 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4573 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4574
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4575<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4576<pre>
Dan Gohman7a5acb52009-01-04 23:49:44 +0000[diff] [blame]4577 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4578 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4579 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4580 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4581</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4582
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4583</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4584
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4585<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4586<h4>
4587 <a name="i_load">'<tt>load</tt>' Instruction</a>
4588</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4589
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4590<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4591
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4592<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4593<pre>
Eli Friedman02e737b2011-08-12 22:50:01 +0000[diff] [blame]4594 &lt;result&gt; = load [volatile] &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4595 &lt;result&gt; = load atomic [volatile] &lt;ty&gt;* &lt;pointer&gt; [singlethread] &lt;ordering&gt;, align &lt;alignment&gt;
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4596 !&lt;index&gt; = !{ i32 1 }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4597</pre>
4598
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4599<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4600<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4601
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4602<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4603<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4604 from which to load. The pointer must point to
4605 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4606 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4607 number or order of execution of this <tt>load</tt> with other <a
4608 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4609
Eli Friedman59b66882011-08-09 23:02:53 +0000[diff] [blame]4610<p>If the <code>load</code> is marked as <code>atomic</code>, it takes an extra
4611 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
4612 argument. The <code>release</code> and <code>acq_rel</code> orderings are
4613 not valid on <code>load</code> instructions. Atomic loads produce <a
4614 href="#memorymodel">defined</a> results when they may see multiple atomic
4615 stores. The type of the pointee must be an integer type whose bit width
4616 is a power of two greater than or equal to eight and less than or equal
4617 to a target-specific size limit. <code>align</code> must be explicitly
4618 specified on atomic loads, and the load has undefined behavior if the
4619 alignment is not set to a value which is at least the size in bytes of
4620 the pointee. <code>!nontemporal</code> does not have any defined semantics
4621 for atomic loads.</p>
4622
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4623<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4624 operation (that is, the alignment of the memory address). A value of 0 or an
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4625 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4626 alignment for the target. It is the responsibility of the code emitter to
4627 ensure that the alignment information is correct. Overestimating the
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4628 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4629 produce less efficient code. An alignment of 1 is always safe.</p>
4630
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4631<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4632 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4633 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4634 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4635 and code generator that this load is not expected to be reused in the cache.
4636 The code generator may select special instructions to save cache bandwidth,
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4637 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4638
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4639<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4640<p>The location of memory pointed to is loaded. If the value being loaded is of
4641 scalar type then the number of bytes read does not exceed the minimum number
4642 of bytes needed to hold all bits of the type. For example, loading an
4643 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4644 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4645 is undefined if the value was not originally written using a store of the
4646 same type.</p>
4647
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4648<h5>Examples:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4649<pre>
4650 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4651 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4652 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4653</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4654
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4655</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4656
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4657<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4658<h4>
4659 <a name="i_store">'<tt>store</tt>' Instruction</a>
4660</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4661
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4662<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4663
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4664<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4665<pre>
Eli Friedman02e737b2011-08-12 22:50:01 +0000[diff] [blame]4666 store [volatile] &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;] <i>; yields {void}</i>
4667 store atomic [volatile] &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt; [singlethread] &lt;ordering&gt;, align &lt;alignment&gt; <i>; yields {void}</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4668</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4669
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4670<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4671<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4672
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4673<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4674<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4675 and an address at which to store it. The type of the
4676 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4677 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4678 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4679 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4680 order of execution of this <tt>store</tt> with other <a
4681 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4682
Eli Friedman59b66882011-08-09 23:02:53 +0000[diff] [blame]4683<p>If the <code>store</code> is marked as <code>atomic</code>, it takes an extra
4684 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
4685 argument. The <code>acquire</code> and <code>acq_rel</code> orderings aren't
4686 valid on <code>store</code> instructions. Atomic loads produce <a
4687 href="#memorymodel">defined</a> results when they may see multiple atomic
4688 stores. The type of the pointee must be an integer type whose bit width
4689 is a power of two greater than or equal to eight and less than or equal
4690 to a target-specific size limit. <code>align</code> must be explicitly
4691 specified on atomic stores, and the store has undefined behavior if the
4692 alignment is not set to a value which is at least the size in bytes of
4693 the pointee. <code>!nontemporal</code> does not have any defined semantics
4694 for atomic stores.</p>
4695
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4696<p>The optional constant "align" argument specifies the alignment of the
4697 operation (that is, the alignment of the memory address). A value of 0 or an
4698 omitted "align" argument means that the operation has the preferential
4699 alignment for the target. It is the responsibility of the code emitter to
4700 ensure that the alignment information is correct. Overestimating the
4701 alignment results in an undefined behavior. Underestimating the alignment may
4702 produce less efficient code. An alignment of 1 is always safe.</p>
4703
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4704<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]4705 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4706 value 1. The existence of the !nontemporal metatadata on the
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4707 instruction tells the optimizer and code generator that this load is
4708 not expected to be reused in the cache. The code generator may
4709 select special instructions to save cache bandwidth, such as the
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4710 MOVNT instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4711
4712
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4713<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4714<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4715 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4716 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4717 does not exceed the minimum number of bytes needed to hold all bits of the
4718 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4719 writing a value of a type like <tt>i20</tt> with a size that is not an
4720 integral number of bytes, it is unspecified what happens to the extra bits
4721 that do not belong to the type, but they will typically be overwritten.</p>
4722
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4723<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4724<pre>
4725 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8830ffe2007-10-22 05:10:05 +0000[diff] [blame]4726 store i32 3, i32* %ptr <i>; yields {void}</i>
4727 %val = <a href="#i_load">load</a> i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4728</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4729
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4730</div>
4731
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4732<!-- _______________________________________________________________________ -->
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]4733<h4>
4734<a name="i_fence">'<tt>fence</tt>' Instruction</a>
4735</h4>
Eli Friedmanfee02c62011-07-25 23:16:38 +0000[diff] [blame]4736
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]4737<div>
Eli Friedmanfee02c62011-07-25 23:16:38 +0000[diff] [blame]4738
4739<h5>Syntax:</h5>
4740<pre>
4741 fence [singlethread] &lt;ordering&gt; <i>; yields {void}</i>
4742</pre>
4743
4744<h5>Overview:</h5>
4745<p>The '<tt>fence</tt>' instruction is used to introduce happens-before edges
4746between operations.</p>
4747
4748<h5>Arguments:</h5> <p>'<code>fence</code>' instructions take an <a
4749href="#ordering">ordering</a> argument which defines what
4750<i>synchronizes-with</i> edges they add. They can only be given
4751<code>acquire</code>, <code>release</code>, <code>acq_rel</code>, and
4752<code>seq_cst</code> orderings.</p>
4753
4754<h5>Semantics:</h5>
4755<p>A fence <var>A</var> which has (at least) <code>release</code> ordering
4756semantics <i>synchronizes with</i> a fence <var>B</var> with (at least)
4757<code>acquire</code> ordering semantics if and only if there exist atomic
4758operations <var>X</var> and <var>Y</var>, both operating on some atomic object
4759<var>M</var>, such that <var>A</var> is sequenced before <var>X</var>,
4760<var>X</var> modifies <var>M</var> (either directly or through some side effect
4761of a sequence headed by <var>X</var>), <var>Y</var> is sequenced before
4762<var>B</var>, and <var>Y</var> observes <var>M</var>. This provides a
4763<i>happens-before</i> dependency between <var>A</var> and <var>B</var>. Rather
4764than an explicit <code>fence</code>, one (but not both) of the atomic operations
4765<var>X</var> or <var>Y</var> might provide a <code>release</code> or
4766<code>acquire</code> (resp.) ordering constraint and still
4767<i>synchronize-with</i> the explicit <code>fence</code> and establish the
4768<i>happens-before</i> edge.</p>
4769
4770<p>A <code>fence</code> which has <code>seq_cst</code> ordering, in addition to
4771having both <code>acquire</code> and <code>release</code> semantics specified
4772above, participates in the global program order of other <code>seq_cst</code>
4773operations and/or fences.</p>
4774
4775<p>The optional "<a href="#singlethread"><code>singlethread</code></a>" argument
4776specifies that the fence only synchronizes with other fences in the same
4777thread. (This is useful for interacting with signal handlers.)</p>
4778
Eli Friedmanfee02c62011-07-25 23:16:38 +0000[diff] [blame]4779<h5>Example:</h5>
4780<pre>
4781 fence acquire <i>; yields {void}</i>
4782 fence singlethread seq_cst <i>; yields {void}</i>
4783</pre>
4784
4785</div>
4786
4787<!-- _______________________________________________________________________ -->
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]4788<h4>
4789<a name="i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a>
4790</h4>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]4791
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]4792<div>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]4793
4794<h5>Syntax:</h5>
4795<pre>
Eli Friedman02e737b2011-08-12 22:50:01 +0000[diff] [blame]4796 cmpxchg [volatile] &lt;ty&gt;* &lt;pointer&gt;, &lt;ty&gt; &lt;cmp&gt;, &lt;ty&gt; &lt;new&gt; [singlethread] &lt;ordering&gt; <i>; yields {ty}</i>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]4797</pre>
4798
4799<h5>Overview:</h5>
4800<p>The '<tt>cmpxchg</tt>' instruction is used to atomically modify memory.
4801It loads a value in memory and compares it to a given value. If they are
4802equal, it stores a new value into the memory.</p>
4803
4804<h5>Arguments:</h5>
4805<p>There are three arguments to the '<code>cmpxchg</code>' instruction: an
4806address to operate on, a value to compare to the value currently be at that
4807address, and a new value to place at that address if the compared values are
4808equal. The type of '<var>&lt;cmp&gt;</var>' must be an integer type whose
4809bit width is a power of two greater than or equal to eight and less than
4810or equal to a target-specific size limit. '<var>&lt;cmp&gt;</var>' and
4811'<var>&lt;new&gt;</var>' must have the same type, and the type of
4812'<var>&lt;pointer&gt;</var>' must be a pointer to that type. If the
4813<code>cmpxchg</code> is marked as <code>volatile</code>, then the
4814optimizer is not allowed to modify the number or order of execution
4815of this <code>cmpxchg</code> with other <a href="#volatile">volatile
4816operations</a>.</p>
4817
4818<!-- FIXME: Extend allowed types. -->
4819
4820<p>The <a href="#ordering"><var>ordering</var></a> argument specifies how this
4821<code>cmpxchg</code> synchronizes with other atomic operations.</p>
4822
4823<p>The optional "<code>singlethread</code>" argument declares that the
4824<code>cmpxchg</code> is only atomic with respect to code (usually signal
4825handlers) running in the same thread as the <code>cmpxchg</code>. Otherwise the
4826cmpxchg is atomic with respect to all other code in the system.</p>
4827
4828<p>The pointer passed into cmpxchg must have alignment greater than or equal to
4829the size in memory of the operand.
4830
4831<h5>Semantics:</h5>
4832<p>The contents of memory at the location specified by the
4833'<tt>&lt;pointer&gt;</tt>' operand is read and compared to
4834'<tt>&lt;cmp&gt;</tt>'; if the read value is the equal,
4835'<tt>&lt;new&gt;</tt>' is written. The original value at the location
4836is returned.
4837
4838<p>A successful <code>cmpxchg</code> is a read-modify-write instruction for the
4839purpose of identifying <a href="#release_sequence">release sequences</a>. A
4840failed <code>cmpxchg</code> is equivalent to an atomic load with an ordering
4841parameter determined by dropping any <code>release</code> part of the
4842<code>cmpxchg</code>'s ordering.</p>
4843
4844<!--
4845FIXME: Is compare_exchange_weak() necessary? (Consider after we've done
4846optimization work on ARM.)
4847
4848FIXME: Is a weaker ordering constraint on failure helpful in practice?
4849-->
4850
4851<h5>Example:</h5>
4852<pre>
4853entry:
4854 %orig = atomic <a href="#i_load">load</a> i32* %ptr unordered <i>; yields {i32}</i>
4855 <a href="#i_br">br</a> label %loop
4856
4857loop:
4858 %cmp = <a href="#i_phi">phi</a> i32 [ %orig, %entry ], [%old, %loop]
4859 %squared = <a href="#i_mul">mul</a> i32 %cmp, %cmp
4860 %old = cmpxchg i32* %ptr, i32 %cmp, i32 %squared <i>; yields {i32}</i>
4861 %success = <a href="#i_icmp">icmp</a> eq i32 %cmp, %old
4862 <a href="#i_br">br</a> i1 %success, label %done, label %loop
4863
4864done:
4865 ...
4866</pre>
4867
4868</div>
4869
4870<!-- _______________________________________________________________________ -->
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]4871<h4>
4872<a name="i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a>
4873</h4>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]4874
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]4875<div>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]4876
4877<h5>Syntax:</h5>
4878<pre>
Eli Friedman02e737b2011-08-12 22:50:01 +0000[diff] [blame]4879 atomicrmw [volatile] &lt;operation&gt; &lt;ty&gt;* &lt;pointer&gt;, &lt;ty&gt; &lt;value&gt; [singlethread] &lt;ordering&gt; <i>; yields {ty}</i>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]4880</pre>
4881
4882<h5>Overview:</h5>
4883<p>The '<tt>atomicrmw</tt>' instruction is used to atomically modify memory.</p>
4884
4885<h5>Arguments:</h5>
4886<p>There are three arguments to the '<code>atomicrmw</code>' instruction: an
4887operation to apply, an address whose value to modify, an argument to the
4888operation. The operation must be one of the following keywords:</p>
4889<ul>
4890 <li>xchg</li>
4891 <li>add</li>
4892 <li>sub</li>
4893 <li>and</li>
4894 <li>nand</li>
4895 <li>or</li>
4896 <li>xor</li>
4897 <li>max</li>
4898 <li>min</li>
4899 <li>umax</li>
4900 <li>umin</li>
4901</ul>
4902
4903<p>The type of '<var>&lt;value&gt;</var>' must be an integer type whose
4904bit width is a power of two greater than or equal to eight and less than
4905or equal to a target-specific size limit. The type of the
4906'<code>&lt;pointer&gt;</code>' operand must be a pointer to that type.
4907If the <code>atomicrmw</code> is marked as <code>volatile</code>, then the
4908optimizer is not allowed to modify the number or order of execution of this
4909<code>atomicrmw</code> with other <a href="#volatile">volatile
4910 operations</a>.</p>
4911
4912<!-- FIXME: Extend allowed types. -->
4913
4914<h5>Semantics:</h5>
4915<p>The contents of memory at the location specified by the
4916'<tt>&lt;pointer&gt;</tt>' operand are atomically read, modified, and written
4917back. The original value at the location is returned. The modification is
4918specified by the <var>operation</var> argument:</p>
4919
4920<ul>
4921 <li>xchg: <code>*ptr = val</code></li>
4922 <li>add: <code>*ptr = *ptr + val</code></li>
4923 <li>sub: <code>*ptr = *ptr - val</code></li>
4924 <li>and: <code>*ptr = *ptr &amp; val</code></li>
4925 <li>nand: <code>*ptr = ~(*ptr &amp; val)</code></li>
4926 <li>or: <code>*ptr = *ptr | val</code></li>
4927 <li>xor: <code>*ptr = *ptr ^ val</code></li>
4928 <li>max: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using a signed comparison)</li>
4929 <li>min: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using a signed comparison)</li>
4930 <li>umax: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using an unsigned comparison)</li>
4931 <li>umin: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using an unsigned comparison)</li>
4932</ul>
4933
4934<h5>Example:</h5>
4935<pre>
4936 %old = atomicrmw add i32* %ptr, i32 1 acquire <i>; yields {i32}</i>
4937</pre>
4938
4939</div>
4940
4941<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4942<h4>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4943 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4944</h4>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4945
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4946<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4947
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4948<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4949<pre>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4950 &lt;result&gt; = getelementptr &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4951 &lt;result&gt; = getelementptr inbounds &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4952</pre>
4953
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4954<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4955<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4956 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4957 It performs address calculation only and does not access memory.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4958
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4959<h5>Arguments:</h5>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4960<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnera40b9122009-07-29 06:44:13 +0000[diff] [blame]4961 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4962 elements of the aggregate object are indexed. The interpretation of each
4963 index is dependent on the type being indexed into. The first index always
4964 indexes the pointer value given as the first argument, the second index
4965 indexes a value of the type pointed to (not necessarily the value directly
4966 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4967 indexed into must be a pointer value, subsequent types can be arrays,
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]4968 vectors, and structs. Note that subsequent types being indexed into
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4969 can never be pointers, since that would require loading the pointer before
4970 continuing calculation.</p>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4971
4972<p>The type of each index argument depends on the type it is indexing into.
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]4973 When indexing into a (optionally packed) structure, only <tt>i32</tt>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4974 integer <b>constants</b> are allowed. When indexing into an array, pointer
4975 or vector, integers of any width are allowed, and they are not required to be
Eli Friedmand8874dc2011-08-12 23:37:55 +0000[diff] [blame]4976 constant. These integers are treated as signed values where relevant.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4977
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4978<p>For example, let's consider a C code fragment and how it gets compiled to
4979 LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4980
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]4981<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4982struct RT {
4983 char A;
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4984 int B[10][20];
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4985 char C;
4986};
4987struct ST {
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4988 int X;
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4989 double Y;
4990 struct RT Z;
4991};
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4992
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4993int *foo(struct ST *s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4994 return &amp;s[1].Z.B[5][13];
4995}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4996</pre>
4997
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4998<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4999
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]5000<pre class="doc_code">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]5001%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
5002%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5003
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]5004define i32* @foo(%ST* %s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5005entry:
5006 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
5007 ret i32* %reg
5008}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5009</pre>
5010
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5011<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5012<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5013 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
5014 }</tt>' type, a structure. The second index indexes into the third element
5015 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
5016 i8 }</tt>' type, another structure. The third index indexes into the second
5017 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
5018 array. The two dimensions of the array are subscripted into, yielding an
5019 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
5020 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5021
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5022<p>Note that it is perfectly legal to index partially through a structure,
5023 returning a pointer to an inner element. Because of this, the LLVM code for
5024 the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5025
5026<pre>
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]5027 define i32* @foo(%ST* %s) {
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5028 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]5029 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
5030 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5031 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
5032 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
5033 ret i32* %t5
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5034 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5035</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]5036
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]5037<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]5038 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
5039 base pointer is not an <i>in bounds</i> address of an allocated object,
5040 or if any of the addresses that would be formed by successive addition of
5041 the offsets implied by the indices to the base address with infinitely
Eli Friedmand8874dc2011-08-12 23:37:55 +0000[diff] [blame]5042 precise signed arithmetic are not an <i>in bounds</i> address of that
5043 allocated object. The <i>in bounds</i> addresses for an allocated object
5044 are all the addresses that point into the object, plus the address one
5045 byte past the end.</p>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]5046
5047<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
Eli Friedmand8874dc2011-08-12 23:37:55 +0000[diff] [blame]5048 the base address with silently-wrapping two's complement arithmetic. If the
5049 offsets have a different width from the pointer, they are sign-extended or
5050 truncated to the width of the pointer. The result value of the
5051 <tt>getelementptr</tt> may be outside the object pointed to by the base
5052 pointer. The result value may not necessarily be used to access memory
5053 though, even if it happens to point into allocated storage. See the
5054 <a href="#pointeraliasing">Pointer Aliasing Rules</a> section for more
5055 information.</p>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]5056
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5057<p>The getelementptr instruction is often confusing. For some more insight into
5058 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]5059
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5060<h5>Example:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5061<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5062 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]5063 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
5064 <i>; yields i8*:vptr</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5065 %vptr = getelementptr {i32, &lt;2 x i8&gt;}* %svptr, i64 0, i32 1, i32 1
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]5066 <i>; yields i8*:eptr</i>
5067 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta0c155e62009-04-25 07:27:44 +0000[diff] [blame]5068 <i>; yields i32*:iptr</i>
Sanjiv Gupta77abea02009-04-24 16:38:13 +0000[diff] [blame]5069 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5070</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5071
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5072</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]5073
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5074</div>
5075
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5076<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5077<h3>
5078 <a name="convertops">Conversion Operations</a>
5079</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5080
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5081<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5082
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5083<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5084 which all take a single operand and a type. They perform various bit
5085 conversions on the operand.</p>
5086
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5087<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5088<h4>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5089 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5090</h4>
5091
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5092<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5093
5094<h5>Syntax:</h5>
5095<pre>
5096 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5097</pre>
5098
5099<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5100<p>The '<tt>trunc</tt>' instruction truncates its operand to the
5101 type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5102
5103<h5>Arguments:</h5>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]5104<p>The '<tt>trunc</tt>' instruction takes a value to trunc, and a type to trunc it to.
5105 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5106 of the same number of integers.
5107 The bit size of the <tt>value</tt> must be larger than
5108 the bit size of the destination type, <tt>ty2</tt>.
5109 Equal sized types are not allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5110
5111<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5112<p>The '<tt>trunc</tt>' instruction truncates the high order bits
5113 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
5114 source size must be larger than the destination size, <tt>trunc</tt> cannot
5115 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5116
5117<h5>Example:</h5>
5118<pre>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]5119 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
5120 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
5121 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
5122 %W = trunc &lt;2 x i16&gt; &lt;i16 8, i16 7&gt; to &lt;2 x i8&gt; <i>; yields &lt;i8 8, i8 7&gt;</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5123</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5124
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5125</div>
5126
5127<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5128<h4>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5129 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5130</h4>
5131
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5132<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5133
5134<h5>Syntax:</h5>
5135<pre>
5136 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5137</pre>
5138
5139<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5140<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5141 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5142
5143
5144<h5>Arguments:</h5>
Nadav Rotem25f2ac92011-02-20 12:37:50 +0000[diff] [blame]5145<p>The '<tt>zext</tt>' instruction takes a value to cast, and a type to cast it to.
5146 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5147 of the same number of integers.
5148 The bit size of the <tt>value</tt> must be smaller than
5149 the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5150 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5151
5152<h5>Semantics:</h5>
5153<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5154 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5155
Reid Spencer07c9c682007-01-12 15:46:11 +0000[diff] [blame]5156<p>When zero extending from i1, the result will always be either 0 or 1.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5157
5158<h5>Example:</h5>
5159<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5160 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5161 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Nadav Rotem25f2ac92011-02-20 12:37:50 +0000[diff] [blame]5162 %Z = zext &lt;2 x i16&gt; &lt;i16 8, i16 7&gt; to &lt;2 x i32&gt; <i>; yields &lt;i32 8, i32 7&gt;</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5163</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5164
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5165</div>
5166
5167<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5168<h4>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5169 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5170</h4>
5171
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5172<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5173
5174<h5>Syntax:</h5>
5175<pre>
5176 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5177</pre>
5178
5179<h5>Overview:</h5>
5180<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
5181
5182<h5>Arguments:</h5>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]5183<p>The '<tt>sext</tt>' instruction takes a value to cast, and a type to cast it to.
5184 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5185 of the same number of integers.
5186 The bit size of the <tt>value</tt> must be smaller than
5187 the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5188 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5189
5190<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5191<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
5192 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
5193 of the type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5194
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5195<p>When sign extending from i1, the extension always results in -1 or 0.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5196
5197<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5198<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5199 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5200 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]5201 %Z = sext &lt;2 x i16&gt; &lt;i16 8, i16 7&gt; to &lt;2 x i32&gt; <i>; yields &lt;i32 8, i32 7&gt;</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5202</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5203
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5204</div>
5205
5206<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5207<h4>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5208 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5209</h4>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5210
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5211<div>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5212
5213<h5>Syntax:</h5>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5214<pre>
5215 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5216</pre>
5217
5218<h5>Overview:</h5>
5219<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5220 <tt>ty2</tt>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5221
5222<h5>Arguments:</h5>
5223<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5224 point</a> value to cast and a <a href="#t_floating">floating point</a> type
5225 to cast it to. The size of <tt>value</tt> must be larger than the size of
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5226 <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5227 <i>no-op cast</i>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5228
5229<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5230<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5231 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5232 <a href="#t_floating">floating point</a> type. If the value cannot fit
5233 within the destination type, <tt>ty2</tt>, then the results are
5234 undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5235
5236<h5>Example:</h5>
5237<pre>
5238 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
5239 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
5240</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5241
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5242</div>
5243
5244<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5245<h4>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5246 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5247</h4>
5248
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5249<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5250
5251<h5>Syntax:</h5>
5252<pre>
5253 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5254</pre>
5255
5256<h5>Overview:</h5>
5257<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5258 floating point value.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5259
5260<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5261<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5262 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
5263 a <a href="#t_floating">floating point</a> type to cast it to. The source
5264 type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5265
5266<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5267<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5268 <a href="#t_floating">floating point</a> type to a larger
5269 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
5270 used to make a <i>no-op cast</i> because it always changes bits. Use
5271 <tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5272
5273<h5>Example:</h5>
5274<pre>
Nick Lewycky9feca672011-03-31 18:20:19 +0000[diff] [blame]5275 %X = fpext float 3.125 to double <i>; yields double:3.125000e+00</i>
5276 %Y = fpext double %X to fp128 <i>; yields fp128:0xL00000000000000004000900000000000</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5277</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5278
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5279</div>
5280
5281<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5282<h4>
Reid Spencer2eadb532007-01-21 00:29:26 +0000[diff] [blame]5283 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5284</h4>
5285
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5286<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5287
5288<h5>Syntax:</h5>
5289<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]5290 &lt;result&gt; = fptoui &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5291</pre>
5292
5293<h5>Overview:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]5294<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5295 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5296
5297<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5298<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
5299 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5300 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5301 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5302 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5303
5304<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5305<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5306 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5307 towards zero) unsigned integer value. If the value cannot fit
5308 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5309
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5310<h5>Example:</h5>
5311<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]5312 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]5313 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]5314 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5315</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5316
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5317</div>
5318
5319<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5320<h4>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5321 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5322</h4>
5323
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5324<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5325
5326<h5>Syntax:</h5>
5327<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5328 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5329</pre>
5330
5331<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5332<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5333 <a href="#t_floating">floating point</a> <tt>value</tt> to
5334 type <tt>ty2</tt>.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5335
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5336<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5337<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
5338 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5339 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5340 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5341 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5342
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5343<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5344<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5345 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5346 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
5347 the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5348
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]5349<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5350<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5351 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]5352 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]5353 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5354</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5355
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5356</div>
5357
5358<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5359<h4>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5360 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5361</h4>
5362
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5363<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5364
5365<h5>Syntax:</h5>
5366<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5367 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5368</pre>
5369
5370<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5371<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5372 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5373
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5374<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]5375<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5376 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5377 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5378 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5379 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5380
5381<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5382<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5383 integer quantity and converts it to the corresponding floating point
5384 value. If the value cannot fit in the floating point value, the results are
5385 undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5386
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5387<h5>Example:</h5>
5388<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5389 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5390 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5391</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5392
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5393</div>
5394
5395<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5396<h4>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5397 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5398</h4>
5399
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5400<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5401
5402<h5>Syntax:</h5>
5403<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5404 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5405</pre>
5406
5407<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5408<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
5409 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5410
5411<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]5412<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5413 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5414 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5415 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5416 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5417
5418<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5419<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
5420 quantity and converts it to the corresponding floating point value. If the
5421 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5422
5423<h5>Example:</h5>
5424<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5425 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5426 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5427</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5428
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5429</div>
5430
5431<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5432<h4>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5433 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5434</h4>
5435
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5436<div>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5437
5438<h5>Syntax:</h5>
5439<pre>
5440 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5441</pre>
5442
5443<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5444<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
5445 the integer type <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5446
5447<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5448<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
5449 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
5450 <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5451
5452<h5>Semantics:</h5>
5453<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5454 <tt>ty2</tt> by interpreting the pointer value as an integer and either
5455 truncating or zero extending that value to the size of the integer type. If
5456 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
5457 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
5458 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
5459 change.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5460
5461<h5>Example:</h5>
5462<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5463 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
5464 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5465</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5466
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5467</div>
5468
5469<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5470<h4>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5471 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5472</h4>
5473
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5474<div>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5475
5476<h5>Syntax:</h5>
5477<pre>
5478 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5479</pre>
5480
5481<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5482<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
5483 pointer type, <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5484
5485<h5>Arguments:</h5>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]5486<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5487 value to cast, and a type to cast it to, which must be a
5488 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5489
5490<h5>Semantics:</h5>
5491<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5492 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
5493 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
5494 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
5495 than the size of a pointer then a zero extension is done. If they are the
5496 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5497
5498<h5>Example:</h5>
5499<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5500 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]5501 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
5502 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5503</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5504
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5505</div>
5506
5507<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5508<h4>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5509 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5510</h4>
5511
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5512<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5513
5514<h5>Syntax:</h5>
5515<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5516 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5517</pre>
5518
5519<h5>Overview:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5520<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5521 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5522
5523<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5524<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
5525 non-aggregate first class value, and a type to cast it to, which must also be
5526 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
5527 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
5528 identical. If the source type is a pointer, the destination type must also be
5529 a pointer. This instruction supports bitwise conversion of vectors to
5530 integers and to vectors of other types (as long as they have the same
5531 size).</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5532
5533<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5534<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5535 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
5536 this conversion. The conversion is done as if the <tt>value</tt> had been
5537 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
5538 be converted to other pointer types with this instruction. To convert
5539 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
5540 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5541
5542<h5>Example:</h5>
5543<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5544 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5545 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5546 %Z = bitcast &lt;2 x int&gt; %V to i64; <i>; yields i64: %V</i>
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]5547</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5548
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5549</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5550
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5551</div>
5552
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5553<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5554<h3>
5555 <a name="otherops">Other Operations</a>
5556</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5557
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5558<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5559
5560<p>The instructions in this category are the "miscellaneous" instructions, which
5561 defy better classification.</p>
5562
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5563<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5564<h4>
5565 <a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
5566</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5567
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5568<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5569
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5570<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5571<pre>
5572 &lt;result&gt; = icmp &lt;cond&gt; &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {i1} or {&lt;N x i1&gt;}:result</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5573</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5574
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5575<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5576<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
5577 boolean values based on comparison of its two integer, integer vector, or
5578 pointer operands.</p>
5579
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5580<h5>Arguments:</h5>
5581<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5582 the condition code indicating the kind of comparison to perform. It is not a
5583 value, just a keyword. The possible condition code are:</p>
5584
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5585<ol>
5586 <li><tt>eq</tt>: equal</li>
5587 <li><tt>ne</tt>: not equal </li>
5588 <li><tt>ugt</tt>: unsigned greater than</li>
5589 <li><tt>uge</tt>: unsigned greater or equal</li>
5590 <li><tt>ult</tt>: unsigned less than</li>
5591 <li><tt>ule</tt>: unsigned less or equal</li>
5592 <li><tt>sgt</tt>: signed greater than</li>
5593 <li><tt>sge</tt>: signed greater or equal</li>
5594 <li><tt>slt</tt>: signed less than</li>
5595 <li><tt>sle</tt>: signed less or equal</li>
5596</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5597
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]5598<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5599 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5600 typed. They must also be identical types.</p>
5601
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5602<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5603<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5604 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5605 either an <a href="#t_integer"><tt>i1</tt></a> or vector of <tt>i1</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5606 result, as follows:</p>
5607
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5608<ol>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5609 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5610 <tt>false</tt> otherwise. No sign interpretation is necessary or
5611 performed.</li>
5612
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5613 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5614 <tt>false</tt> otherwise. No sign interpretation is necessary or
5615 performed.</li>
5616
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5617 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5618 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5619
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5620 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5621 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5622 to <tt>op2</tt>.</li>
5623
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5624 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5625 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5626
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5627 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5628 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5629
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5630 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5631 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5632
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5633 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5634 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5635 to <tt>op2</tt>.</li>
5636
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5637 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5638 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5639
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5640 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5641 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5642</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5643
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5644<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5645 values are compared as if they were integers.</p>
5646
5647<p>If the operands are integer vectors, then they are compared element by
5648 element. The result is an <tt>i1</tt> vector with the same number of elements
5649 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5650
5651<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5652<pre>
5653 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5654 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5655 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5656 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5657 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5658 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5659</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5660
5661<p>Note that the code generator does not yet support vector types with
5662 the <tt>icmp</tt> instruction.</p>
5663
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5664</div>
5665
5666<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5667<h4>
5668 <a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5669</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5670
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5671<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5672
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5673<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5674<pre>
5675 &lt;result&gt; = fcmp &lt;cond&gt; &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {i1} or {&lt;N x i1&gt;}:result</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5676</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5677
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5678<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5679<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5680 values based on comparison of its operands.</p>
5681
5682<p>If the operands are floating point scalars, then the result type is a boolean
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5683(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5684
5685<p>If the operands are floating point vectors, then the result type is a vector
5686 of boolean with the same number of elements as the operands being
5687 compared.</p>
5688
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5689<h5>Arguments:</h5>
5690<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5691 the condition code indicating the kind of comparison to perform. It is not a
5692 value, just a keyword. The possible condition code are:</p>
5693
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5694<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5695 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5696 <li><tt>oeq</tt>: ordered and equal</li>
5697 <li><tt>ogt</tt>: ordered and greater than </li>
5698 <li><tt>oge</tt>: ordered and greater than or equal</li>
5699 <li><tt>olt</tt>: ordered and less than </li>
5700 <li><tt>ole</tt>: ordered and less than or equal</li>
5701 <li><tt>one</tt>: ordered and not equal</li>
5702 <li><tt>ord</tt>: ordered (no nans)</li>
5703 <li><tt>ueq</tt>: unordered or equal</li>
5704 <li><tt>ugt</tt>: unordered or greater than </li>
5705 <li><tt>uge</tt>: unordered or greater than or equal</li>
5706 <li><tt>ult</tt>: unordered or less than </li>
5707 <li><tt>ule</tt>: unordered or less than or equal</li>
5708 <li><tt>une</tt>: unordered or not equal</li>
5709 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5710 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5711</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5712
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5713<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5714 <i>unordered</i> means that either operand may be a QNAN.</p>
5715
5716<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5717 a <a href="#t_floating">floating point</a> type or
5718 a <a href="#t_vector">vector</a> of floating point type. They must have
5719 identical types.</p>
5720
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5721<h5>Semantics:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]5722<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5723 according to the condition code given as <tt>cond</tt>. If the operands are
5724 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5725 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5726 follows:</p>
5727
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5728<ol>
5729 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5730
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5731 <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5732 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5733
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5734 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5735 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5736
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5737 <li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5738 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5739
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5740 <li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5741 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5742
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5743 <li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5744 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5745
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5746 <li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5747 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5748
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5749 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5750
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5751 <li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5752 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5753
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5754 <li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5755 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5756
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5757 <li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5758 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5759
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5760 <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5761 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5762
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5763 <li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5764 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5765
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5766 <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5767 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5768
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5769 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5770
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5771 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5772</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5773
5774<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5775<pre>
5776 &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
Dan Gohmanc579d972008-09-09 01:02:47 +0000[diff] [blame]5777 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5778 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5779 &lt;result&gt; = fcmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5780</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5781
5782<p>Note that the code generator does not yet support vector types with
5783 the <tt>fcmp</tt> instruction.</p>
5784
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5785</div>
5786
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5787<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5788<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5789 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5790</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5791
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5792<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5793
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5794<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5795<pre>
5796 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5797</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5798
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5799<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5800<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5801 SSA graph representing the function.</p>
5802
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5803<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5804<p>The type of the incoming values is specified with the first type field. After
5805 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5806 one pair for each predecessor basic block of the current block. Only values
5807 of <a href="#t_firstclass">first class</a> type may be used as the value
5808 arguments to the PHI node. Only labels may be used as the label
5809 arguments.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5810
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5811<p>There must be no non-phi instructions between the start of a basic block and
5812 the PHI instructions: i.e. PHI instructions must be first in a basic
5813 block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5814
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5815<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5816 occur on the edge from the corresponding predecessor block to the current
5817 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5818 value on the same edge).</p>
Jay Foad1a4eea52009-06-03 10:20:10 +0000[diff] [blame]5819
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5820<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5821<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5822 specified by the pair corresponding to the predecessor basic block that
5823 executed just prior to the current block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5824
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5825<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5826<pre>
5827Loop: ; Infinite loop that counts from 0 on up...
5828 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5829 %nextindvar = add i32 %indvar, 1
5830 br label %Loop
5831</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5832
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5833</div>
5834
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5835<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5836<h4>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5837 <a name="i_select">'<tt>select</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5838</h4>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5839
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5840<div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5841
5842<h5>Syntax:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5843<pre>
Dan Gohmanc579d972008-09-09 01:02:47 +0000[diff] [blame]5844 &lt;result&gt; = select <i>selty</i> &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
5845
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5846 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5847</pre>
5848
5849<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5850<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5851 condition, without branching.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5852
5853
5854<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5855<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5856 values indicating the condition, and two values of the
5857 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5858 vectors and the condition is a scalar, then entire vectors are selected, not
5859 individual elements.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5860
5861<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5862<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5863 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5864
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5865<p>If the condition is a vector of i1, then the value arguments must be vectors
5866 of the same size, and the selection is done element by element.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5867
5868<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5869<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5870 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5871</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5872
5873<p>Note that the code generator does not yet support conditions
5874 with vector type.</p>
5875
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5876</div>
5877
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]5878<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5879<h4>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5880 <a name="i_call">'<tt>call</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5881</h4>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5882
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5883<div>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5884
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5885<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5886<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]5887 &lt;result&gt; = [tail] call [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>] &lt;ty&gt; [&lt;fnty&gt;*] &lt;fnptrval&gt;(&lt;function args&gt;) [<a href="#fnattrs">fn attrs</a>]
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5888</pre>
5889
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5890<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5891<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5892
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5893<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5894<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5895
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5896<ol>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5897 <li>The optional "tail" marker indicates that the callee function does not
5898 access any allocas or varargs in the caller. Note that calls may be
5899 marked "tail" even if they do not occur before
5900 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5901 present, the function call is eligible for tail call optimization,
5902 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Cheng59676492010-03-08 21:05:02 +0000[diff] [blame]5903 optimized into a jump</a>. The code generator may optimize calls marked
5904 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5905 sibling call optimization</a> when the caller and callee have
5906 matching signatures, or 2) forced tail call optimization when the
5907 following extra requirements are met:
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5908 <ul>
5909 <li>Caller and callee both have the calling
5910 convention <tt>fastcc</tt>.</li>
5911 <li>The call is in tail position (ret immediately follows call and ret
5912 uses value of call or is void).</li>
5913 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohman6232f732010-03-02 01:08:11 +0000[diff] [blame]5914 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5915 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5916 constraints are met.</a></li>
5917 </ul>
5918 </li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5919
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5920 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5921 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5922 defaults to using C calling conventions. The calling convention of the
5923 call must match the calling convention of the target function, or else the
5924 behavior is undefined.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5925
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5926 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5927 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5928 '<tt>inreg</tt>' attributes are valid here.</li>
5929
5930 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5931 type of the return value. Functions that return no value are marked
5932 <tt><a href="#t_void">void</a></tt>.</li>
5933
5934 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5935 being invoked. The argument types must match the types implied by this
5936 signature. This type can be omitted if the function is not varargs and if
5937 the function type does not return a pointer to a function.</li>
5938
5939 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5940 be invoked. In most cases, this is a direct function invocation, but
5941 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5942 to function value.</li>
5943
5944 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]5945 signature argument types and parameter attributes. All arguments must be
5946 of <a href="#t_firstclass">first class</a> type. If the function
5947 signature indicates the function accepts a variable number of arguments,
5948 the extra arguments can be specified.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5949
5950 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5951 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5952 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5953</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5954
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5955<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5956<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5957 a specified function, with its incoming arguments bound to the specified
5958 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5959 function, control flow continues with the instruction after the function
5960 call, and the return value of the function is bound to the result
5961 argument.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5962
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5963<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5964<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]5965 %retval = call i32 @test(i32 %argc)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5966 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]5967 %X = tail call i32 @foo() <i>; yields i32</i>
5968 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5969 call void %foo(i8 97 signext)
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]5970
5971 %struct.A = type { i32, i8 }
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5972 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]5973 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5974 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner6cbe8e92008-10-08 06:26:11 +0000[diff] [blame]5975 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmaneefa7df2008-10-07 10:03:45 +0000[diff] [blame]5976 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5977</pre>
5978
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5979<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen722212d2009-09-25 17:04:42 +0000[diff] [blame]5980standard C99 library as being the C99 library functions, and may perform
5981optimizations or generate code for them under that assumption. This is
5982something we'd like to change in the future to provide better support for
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5983freestanding environments and non-C-based languages.</p>
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5984
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5985</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5986
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5987<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5988<h4>
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]5989 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5990</h4>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5991
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5992<div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5993
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5994<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5995<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5996 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5997</pre>
5998
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5999<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6000<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6001 the "variable argument" area of a function call. It is used to implement the
6002 <tt>va_arg</tt> macro in C.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6003
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6004<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6005<p>This instruction takes a <tt>va_list*</tt> value and the type of the
6006 argument. It returns a value of the specified argument type and increments
6007 the <tt>va_list</tt> to point to the next argument. The actual type
6008 of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6009
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6010<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6011<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
6012 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
6013 to the next argument. For more information, see the variable argument
6014 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6015
6016<p>It is legal for this instruction to be called in a function which does not
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6017 take a variable number of arguments, for example, the <tt>vfprintf</tt>
6018 function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6019
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6020<p><tt>va_arg</tt> is an LLVM instruction instead of
6021 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
6022 argument.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6023
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6024<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6025<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
6026
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6027<p>Note that the code generator does not yet fully support va_arg on many
6028 targets. Also, it does not currently support va_arg with aggregate types on
6029 any target.</p>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]6030
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6031</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6032
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6033<!-- _______________________________________________________________________ -->
6034<h4>
6035 <a name="i_landingpad">'<tt>landingpad</tt>' Instruction</a>
6036</h4>
6037
6038<div>
6039
6040<h5>Syntax:</h5>
6041<pre>
Bill Wendling49bfb122011-08-08 08:06:05 +0000[diff] [blame]6042 &lt;resultval&gt; = landingpad &lt;somety&gt; personality &lt;type&gt; &lt;pers_fn&gt; &lt;clause&gt;+
6043 &lt;resultval&gt; = landingpad &lt;somety&gt; personality &lt;type&gt; &lt;pers_fn&gt; cleanup &lt;clause&gt;*
6044
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6045 &lt;clause&gt; := catch &lt;type&gt; &lt;value&gt;
Bill Wendlingfae14752011-08-12 20:24:12 +0000[diff] [blame]6046 &lt;clause&gt; := filter &lt;array constant type&gt; &lt;array constant&gt;
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6047</pre>
6048
6049<h5>Overview:</h5>
6050<p>The '<tt>landingpad</tt>' instruction is used by
6051 <a href="ExceptionHandling.html#overview">LLVM's exception handling
6052 system</a> to specify that a basic block is a landing pad &mdash; one where
6053 the exception lands, and corresponds to the code found in the
6054 <i><tt>catch</tt></i> portion of a <i><tt>try/catch</tt></i> sequence. It
6055 defines values supplied by the personality function (<tt>pers_fn</tt>) upon
6056 re-entry to the function. The <tt>resultval</tt> has the
6057 type <tt>somety</tt>.</p>
6058
6059<h5>Arguments:</h5>
6060<p>This instruction takes a <tt>pers_fn</tt> value. This is the personality
6061 function associated with the unwinding mechanism. The optional
6062 <tt>cleanup</tt> flag indicates that the landing pad block is a cleanup.</p>
6063
6064<p>A <tt>clause</tt> begins with the clause type &mdash; <tt>catch</tt>
Bill Wendlingfae14752011-08-12 20:24:12 +0000[diff] [blame]6065 or <tt>filter</tt> &mdash; and contains the global variable representing the
6066 "type" that may be caught or filtered respectively. Unlike the
6067 <tt>catch</tt> clause, the <tt>filter</tt> clause takes an array constant as
6068 its argument. Use "<tt>[0 x i8**] undef</tt>" for a filter which cannot
6069 throw. The '<tt>landingpad</tt>' instruction must contain <em>at least</em>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6070 one <tt>clause</tt> or the <tt>cleanup</tt> flag.</p>
6071
6072<h5>Semantics:</h5>
6073<p>The '<tt>landingpad</tt>' instruction defines the values which are set by the
6074 personality function (<tt>pers_fn</tt>) upon re-entry to the function, and
6075 therefore the "result type" of the <tt>landingpad</tt> instruction. As with
6076 calling conventions, how the personality function results are represented in
6077 LLVM IR is target specific.</p>
6078
Bill Wendling0524b8d2011-08-03 17:17:06 +0000[diff] [blame]6079<p>The clauses are applied in order from top to bottom. If two
6080 <tt>landingpad</tt> instructions are merged together through inlining, the
Bill Wendlinga503fc02011-08-08 07:58:58 +0000[diff] [blame]6081 clauses from the calling function are appended to the list of clauses.</p>
Bill Wendling0524b8d2011-08-03 17:17:06 +0000[diff] [blame]6082
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6083<p>The <tt>landingpad</tt> instruction has several restrictions:</p>
6084
6085<ul>
6086 <li>A landing pad block is a basic block which is the unwind destination of an
6087 '<tt>invoke</tt>' instruction.</li>
6088 <li>A landing pad block must have a '<tt>landingpad</tt>' instruction as its
6089 first non-PHI instruction.</li>
6090 <li>There can be only one '<tt>landingpad</tt>' instruction within the landing
6091 pad block.</li>
6092 <li>A basic block that is not a landing pad block may not include a
6093 '<tt>landingpad</tt>' instruction.</li>
6094 <li>All '<tt>landingpad</tt>' instructions in a function must have the same
6095 personality function.</li>
6096</ul>
6097
6098<h5>Example:</h5>
6099<pre>
6100 ;; A landing pad which can catch an integer.
6101 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6102 catch i8** @_ZTIi
6103 ;; A landing pad that is a cleanup.
6104 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
Bill Wendlingfae14752011-08-12 20:24:12 +0000[diff] [blame]6105 cleanup
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6106 ;; A landing pad which can catch an integer and can only throw a double.
6107 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6108 catch i8** @_ZTIi
Bill Wendlingfae14752011-08-12 20:24:12 +0000[diff] [blame]6109 filter [1 x i8**] [@_ZTId]
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6110</pre>
6111
6112</div>
6113
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6114</div>
6115
6116</div>
6117
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6118<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6119<h2><a name="intrinsics">Intrinsic Functions</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]6120<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6121
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6122<div>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6123
6124<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6125 well known names and semantics and are required to follow certain
6126 restrictions. Overall, these intrinsics represent an extension mechanism for
6127 the LLVM language that does not require changing all of the transformations
6128 in LLVM when adding to the language (or the bitcode reader/writer, the
6129 parser, etc...).</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6130
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]6131<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6132 prefix is reserved in LLVM for intrinsic names; thus, function names may not
6133 begin with this prefix. Intrinsic functions must always be external
6134 functions: you cannot define the body of intrinsic functions. Intrinsic
6135 functions may only be used in call or invoke instructions: it is illegal to
6136 take the address of an intrinsic function. Additionally, because intrinsic
6137 functions are part of the LLVM language, it is required if any are added that
6138 they be documented here.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6139
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6140<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
6141 family of functions that perform the same operation but on different data
6142 types. Because LLVM can represent over 8 million different integer types,
6143 overloading is used commonly to allow an intrinsic function to operate on any
6144 integer type. One or more of the argument types or the result type can be
6145 overloaded to accept any integer type. Argument types may also be defined as
6146 exactly matching a previous argument's type or the result type. This allows
6147 an intrinsic function which accepts multiple arguments, but needs all of them
6148 to be of the same type, to only be overloaded with respect to a single
6149 argument or the result.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6150
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6151<p>Overloaded intrinsics will have the names of its overloaded argument types
6152 encoded into its function name, each preceded by a period. Only those types
6153 which are overloaded result in a name suffix. Arguments whose type is matched
6154 against another type do not. For example, the <tt>llvm.ctpop</tt> function
6155 can take an integer of any width and returns an integer of exactly the same
6156 integer width. This leads to a family of functions such as
6157 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
6158 %val)</tt>. Only one type, the return type, is overloaded, and only one type
6159 suffix is required. Because the argument's type is matched against the return
6160 type, it does not require its own name suffix.</p>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6161
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6162<p>To learn how to add an intrinsic function, please see the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6163 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6164
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6165<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6166<h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6167 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6168</h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6169
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6170<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6171
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6172<p>Variable argument support is defined in LLVM with
6173 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
6174 intrinsic functions. These functions are related to the similarly named
6175 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6176
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6177<p>All of these functions operate on arguments that use a target-specific value
6178 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
6179 not define what this type is, so all transformations should be prepared to
6180 handle these functions regardless of the type used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6181
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]6182<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6183 instruction and the variable argument handling intrinsic functions are
6184 used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6185
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]6186<pre class="doc_code">
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6187define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6188 ; Initialize variable argument processing
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6189 %ap = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6190 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6191 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6192
6193 ; Read a single integer argument
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6194 %tmp = va_arg i8** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6195
6196 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6197 %aq = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6198 %aq2 = bitcast i8** %aq to i8*
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6199 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6200 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6201
6202 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6203 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]6204 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6205}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6206
6207declare void @llvm.va_start(i8*)
6208declare void @llvm.va_copy(i8*, i8*)
6209declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6210</pre>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6211
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6212<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6213<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6214 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6215</h4>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6216
6217
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6218<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6219
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6220<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6221<pre>
6222 declare void %llvm.va_start(i8* &lt;arglist&gt;)
6223</pre>
6224
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6225<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6226<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
6227 for subsequent use by <tt><a href="#i_va_arg">va_arg</a></tt>.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6228
6229<h5>Arguments:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]6230<p>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6231
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6232<h5>Semantics:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]6233<p>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6234 macro available in C. In a target-dependent way, it initializes
6235 the <tt>va_list</tt> element to which the argument points, so that the next
6236 call to <tt>va_arg</tt> will produce the first variable argument passed to
6237 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
6238 need to know the last argument of the function as the compiler can figure
6239 that out.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6240
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6241</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6242
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6243<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6244<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6245 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6246</h4>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6247
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6248<div>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6249
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6250<h5>Syntax:</h5>
6251<pre>
6252 declare void @llvm.va_end(i8* &lt;arglist&gt;)
6253</pre>
6254
6255<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6256<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6257 which has been initialized previously
6258 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
6259 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6260
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6261<h5>Arguments:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6262<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6263
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6264<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6265<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6266 macro available in C. In a target-dependent way, it destroys
6267 the <tt>va_list</tt> element to which the argument points. Calls
6268 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
6269 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
6270 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6271
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6272</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6273
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6274<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6275<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6276 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6277</h4>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6278
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6279<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6280
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6281<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6282<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6283 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6284</pre>
6285
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6286<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6287<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6288 from the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6289
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6290<h5>Arguments:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6291<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6292 The second argument is a pointer to a <tt>va_list</tt> element to copy
6293 from.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6294
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6295<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6296<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6297 macro available in C. In a target-dependent way, it copies the
6298 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
6299 element. This intrinsic is necessary because
6300 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
6301 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6302
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6303</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6304
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6305</div>
6306
Bill Wendling537603b2011-07-31 06:45:03 +0000[diff] [blame]6307</div>
6308
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6309<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6310<h3>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6311 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6312</h3>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6313
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6314<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6315
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6316<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]6317Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6318intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
6319roots on the stack</a>, as well as garbage collector implementations that
6320require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
6321barriers. Front-ends for type-safe garbage collected languages should generate
6322these intrinsics to make use of the LLVM garbage collectors. For more details,
6323see <a href="GarbageCollection.html">Accurate Garbage Collection with
6324LLVM</a>.</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]6325
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6326<p>The garbage collection intrinsics only operate on objects in the generic
6327 address space (address space zero).</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]6328
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6329<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6330<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6331 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6332</h4>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6333
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6334<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6335
6336<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6337<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]6338 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6339</pre>
6340
6341<h5>Overview:</h5>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]6342<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6343 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6344
6345<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6346<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6347 root pointer. The second pointer (which must be either a constant or a
6348 global value address) contains the meta-data to be associated with the
6349 root.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6350
6351<h5>Semantics:</h5>
Chris Lattner851b7712008-04-24 05:59:56 +0000[diff] [blame]6352<p>At runtime, a call to this intrinsic stores a null pointer into the "ptrloc"
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6353 location. At compile-time, the code generator generates information to allow
6354 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
6355 intrinsic may only be used in a function which <a href="#gc">specifies a GC
6356 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6357
6358</div>
6359
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6360<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6361<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6362 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6363</h4>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6364
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6365<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6366
6367<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6368<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]6369 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6370</pre>
6371
6372<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6373<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6374 locations, allowing garbage collector implementations that require read
6375 barriers.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6376
6377<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]6378<p>The second argument is the address to read from, which should be an address
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6379 allocated from the garbage collector. The first object is a pointer to the
6380 start of the referenced object, if needed by the language runtime (otherwise
6381 null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6382
6383<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6384<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6385 instruction, but may be replaced with substantially more complex code by the
6386 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
6387 may only be used in a function which <a href="#gc">specifies a GC
6388 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6389
6390</div>
6391
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6392<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6393<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6394 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6395</h4>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6396
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6397<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6398
6399<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6400<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]6401 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6402</pre>
6403
6404<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6405<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6406 locations, allowing garbage collector implementations that require write
6407 barriers (such as generational or reference counting collectors).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6408
6409<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]6410<p>The first argument is the reference to store, the second is the start of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6411 object to store it to, and the third is the address of the field of Obj to
6412 store to. If the runtime does not require a pointer to the object, Obj may
6413 be null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6414
6415<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6416<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6417 instruction, but may be replaced with substantially more complex code by the
6418 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
6419 may only be used in a function which <a href="#gc">specifies a GC
6420 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6421
6422</div>
6423
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6424</div>
6425
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6426<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6427<h3>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6428 <a name="int_codegen">Code Generator Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6429</h3>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6430
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6431<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6432
6433<p>These intrinsics are provided by LLVM to expose special features that may
6434 only be implemented with code generator support.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6435
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6436<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6437<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6438 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6439</h4>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6440
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6441<div>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6442
6443<h5>Syntax:</h5>
6444<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6445 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6446</pre>
6447
6448<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6449<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
6450 target-specific value indicating the return address of the current function
6451 or one of its callers.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6452
6453<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6454<p>The argument to this intrinsic indicates which function to return the address
6455 for. Zero indicates the calling function, one indicates its caller, etc.
6456 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6457
6458<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6459<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
6460 indicating the return address of the specified call frame, or zero if it
6461 cannot be identified. The value returned by this intrinsic is likely to be
6462 incorrect or 0 for arguments other than zero, so it should only be used for
6463 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6464
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6465<p>Note that calling this intrinsic does not prevent function inlining or other
6466 aggressive transformations, so the value returned may not be that of the
6467 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6468
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6469</div>
6470
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6471<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6472<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6473 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6474</h4>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6475
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6476<div>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6477
6478<h5>Syntax:</h5>
6479<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6480 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6481</pre>
6482
6483<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6484<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
6485 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6486
6487<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6488<p>The argument to this intrinsic indicates which function to return the frame
6489 pointer for. Zero indicates the calling function, one indicates its caller,
6490 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6491
6492<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6493<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
6494 indicating the frame address of the specified call frame, or zero if it
6495 cannot be identified. The value returned by this intrinsic is likely to be
6496 incorrect or 0 for arguments other than zero, so it should only be used for
6497 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6498
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6499<p>Note that calling this intrinsic does not prevent function inlining or other
6500 aggressive transformations, so the value returned may not be that of the
6501 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6502
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6503</div>
6504
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6505<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6506<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6507 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6508</h4>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6509
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6510<div>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6511
6512<h5>Syntax:</h5>
6513<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6514 declare i8* @llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6515</pre>
6516
6517<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6518<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
6519 of the function stack, for use
6520 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
6521 useful for implementing language features like scoped automatic variable
6522 sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6523
6524<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6525<p>This intrinsic returns a opaque pointer value that can be passed
6526 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
6527 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
6528 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
6529 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
6530 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
6531 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6532
6533</div>
6534
6535<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6536<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6537 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6538</h4>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6539
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6540<div>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6541
6542<h5>Syntax:</h5>
6543<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6544 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6545</pre>
6546
6547<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6548<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
6549 the function stack to the state it was in when the
6550 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
6551 executed. This is useful for implementing language features like scoped
6552 automatic variable sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6553
6554<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6555<p>See the description
6556 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6557
6558</div>
6559
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6560<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6561<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6562 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6563</h4>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6564
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6565<div>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6566
6567<h5>Syntax:</h5>
6568<pre>
Bruno Cardoso Lopesdc9ff3a2011-06-14 04:58:37 +0000[diff] [blame]6569 declare void @llvm.prefetch(i8* &lt;address&gt;, i32 &lt;rw&gt;, i32 &lt;locality&gt;, i32 &lt;cache type&gt;)
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6570</pre>
6571
6572<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6573<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
6574 insert a prefetch instruction if supported; otherwise, it is a noop.
6575 Prefetches have no effect on the behavior of the program but can change its
6576 performance characteristics.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6577
6578<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6579<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
6580 specifier determining if the fetch should be for a read (0) or write (1),
6581 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Bruno Cardoso Lopesdc9ff3a2011-06-14 04:58:37 +0000[diff] [blame]6582 locality, to (3) - extremely local keep in cache. The <tt>cache type</tt>
6583 specifies whether the prefetch is performed on the data (1) or instruction (0)
6584 cache. The <tt>rw</tt>, <tt>locality</tt> and <tt>cache type</tt> arguments
6585 must be constant integers.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6586
6587<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6588<p>This intrinsic does not modify the behavior of the program. In particular,
6589 prefetches cannot trap and do not produce a value. On targets that support
6590 this intrinsic, the prefetch can provide hints to the processor cache for
6591 better performance.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6592
6593</div>
6594
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6595<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6596<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6597 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6598</h4>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6599
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6600<div>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6601
6602<h5>Syntax:</h5>
6603<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]6604 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6605</pre>
6606
6607<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6608<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
6609 Counter (PC) in a region of code to simulators and other tools. The method
6610 is target specific, but it is expected that the marker will use exported
6611 symbols to transmit the PC of the marker. The marker makes no guarantees
6612 that it will remain with any specific instruction after optimizations. It is
6613 possible that the presence of a marker will inhibit optimizations. The
6614 intended use is to be inserted after optimizations to allow correlations of
6615 simulation runs.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6616
6617<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6618<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6619
6620<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6621<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6622 not support this intrinsic may ignore it.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6623
6624</div>
6625
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6626<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6627<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6628 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6629</h4>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6630
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6631<div>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6632
6633<h5>Syntax:</h5>
6634<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]6635 declare i64 @llvm.readcyclecounter()
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6636</pre>
6637
6638<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6639<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
6640 counter register (or similar low latency, high accuracy clocks) on those
6641 targets that support it. On X86, it should map to RDTSC. On Alpha, it
6642 should map to RPCC. As the backing counters overflow quickly (on the order
6643 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6644
6645<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6646<p>When directly supported, reading the cycle counter should not modify any
6647 memory. Implementations are allowed to either return a application specific
6648 value or a system wide value. On backends without support, this is lowered
6649 to a constant 0.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6650
6651</div>
6652
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6653</div>
6654
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6655<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6656<h3>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6657 <a name="int_libc">Standard C Library Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6658</h3>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6659
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6660<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6661
6662<p>LLVM provides intrinsics for a few important standard C library functions.
6663 These intrinsics allow source-language front-ends to pass information about
6664 the alignment of the pointer arguments to the code generator, providing
6665 opportunity for more efficient code generation.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6666
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6667<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6668<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6669 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6670</h4>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6671
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6672<div>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6673
6674<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6675<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
Mon P Wang508127b2010-04-07 06:35:53 +0000[diff] [blame]6676 integer bit width and for different address spaces. Not all targets support
6677 all bit widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6678
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6679<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6680 declare void @llvm.memcpy.p0i8.p0i8.i32(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6681 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6682 declare void @llvm.memcpy.p0i8.p0i8.i64(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6683 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6684</pre>
6685
6686<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6687<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6688 source location to the destination location.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6689
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6690<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6691 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6692 and the pointers can be in specified address spaces.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6693
6694<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6695
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6696<p>The first argument is a pointer to the destination, the second is a pointer
6697 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6698 number of bytes to copy, the fourth argument is the alignment of the
6699 source and destination locations, and the fifth is a boolean indicating a
6700 volatile access.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6701
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6702<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6703 then the caller guarantees that both the source and destination pointers are
6704 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]6705
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6706<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6707 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6708 The detailed access behavior is not very cleanly specified and it is unwise
6709 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6710
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6711<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6712
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6713<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6714 source location to the destination location, which are not allowed to
6715 overlap. It copies "len" bytes of memory over. If the argument is known to
6716 be aligned to some boundary, this can be specified as the fourth argument,
6717 otherwise it should be set to 0 or 1.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6718
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6719</div>
6720
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6721<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6722<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6723 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6724</h4>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6725
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6726<div>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6727
6728<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]6729<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
Mon P Wang508127b2010-04-07 06:35:53 +0000[diff] [blame]6730 width and for different address space. Not all targets support all bit
6731 widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6732
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6733<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6734 declare void @llvm.memmove.p0i8.p0i8.i32(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6735 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6736 declare void @llvm.memmove.p0i8.p0i8.i64(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6737 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6738</pre>
6739
6740<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6741<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6742 source location to the destination location. It is similar to the
6743 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6744 overlap.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6745
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6746<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6747 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6748 and the pointers can be in specified address spaces.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6749
6750<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6751
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6752<p>The first argument is a pointer to the destination, the second is a pointer
6753 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6754 number of bytes to copy, the fourth argument is the alignment of the
6755 source and destination locations, and the fifth is a boolean indicating a
6756 volatile access.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6757
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6758<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6759 then the caller guarantees that the source and destination pointers are
6760 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]6761
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6762<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6763 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6764 The detailed access behavior is not very cleanly specified and it is unwise
6765 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6766
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6767<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6768
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6769<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6770 source location to the destination location, which may overlap. It copies
6771 "len" bytes of memory over. If the argument is known to be aligned to some
6772 boundary, this can be specified as the fourth argument, otherwise it should
6773 be set to 0 or 1.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6774
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6775</div>
6776
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6777<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6778<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6779 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6780</h4>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6781
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6782<div>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6783
6784<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]6785<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]6786 width and for different address spaces. However, not all targets support all
6787 bit widths.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6788
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6789<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6790 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]6791 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6792 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]6793 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6794</pre>
6795
6796<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6797<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6798 particular byte value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6799
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6800<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]6801 intrinsic does not return a value and takes extra alignment/volatile
6802 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6803
6804<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6805<p>The first argument is a pointer to the destination to fill, the second is the
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]6806 byte value with which to fill it, the third argument is an integer argument
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6807 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]6808 alignment of the destination location.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6809
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6810<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6811 then the caller guarantees that the destination pointer is aligned to that
6812 boundary.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6813
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6814<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6815 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6816 The detailed access behavior is not very cleanly specified and it is unwise
6817 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6818
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6819<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6820<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6821 at the destination location. If the argument is known to be aligned to some
6822 boundary, this can be specified as the fourth argument, otherwise it should
6823 be set to 0 or 1.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6824
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6825</div>
6826
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]6827<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6828<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6829 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6830</h4>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6831
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6832<div>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6833
6834<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6835<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6836 floating point or vector of floating point type. Not all targets support all
6837 types however.</p>
6838
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6839<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6840 declare float @llvm.sqrt.f32(float %Val)
6841 declare double @llvm.sqrt.f64(double %Val)
6842 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6843 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6844 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6845</pre>
6846
6847<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6848<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6849 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6850 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6851 behavior for negative numbers other than -0.0 (which allows for better
6852 optimization, because there is no need to worry about errno being
6853 set). <tt>llvm.sqrt(-0.0)</tt> is defined to return -0.0 like IEEE sqrt.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6854
6855<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6856<p>The argument and return value are floating point numbers of the same
6857 type.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6858
6859<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6860<p>This function returns the sqrt of the specified operand if it is a
6861 nonnegative floating point number.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6862
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6863</div>
6864
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6865<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6866<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6867 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6868</h4>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6869
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6870<div>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6871
6872<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6873<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6874 floating point or vector of floating point type. Not all targets support all
6875 types however.</p>
6876
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6877<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6878 declare float @llvm.powi.f32(float %Val, i32 %power)
6879 declare double @llvm.powi.f64(double %Val, i32 %power)
6880 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6881 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6882 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6883</pre>
6884
6885<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6886<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6887 specified (positive or negative) power. The order of evaluation of
6888 multiplications is not defined. When a vector of floating point type is
6889 used, the second argument remains a scalar integer value.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6890
6891<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6892<p>The second argument is an integer power, and the first is a value to raise to
6893 that power.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6894
6895<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6896<p>This function returns the first value raised to the second power with an
6897 unspecified sequence of rounding operations.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6898
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6899</div>
6900
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6901<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6902<h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6903 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6904</h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6905
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6906<div>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6907
6908<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6909<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6910 floating point or vector of floating point type. Not all targets support all
6911 types however.</p>
6912
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6913<pre>
6914 declare float @llvm.sin.f32(float %Val)
6915 declare double @llvm.sin.f64(double %Val)
6916 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6917 declare fp128 @llvm.sin.f128(fp128 %Val)
6918 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6919</pre>
6920
6921<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6922<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6923
6924<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6925<p>The argument and return value are floating point numbers of the same
6926 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6927
6928<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6929<p>This function returns the sine of the specified operand, returning the same
6930 values as the libm <tt>sin</tt> functions would, and handles error conditions
6931 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6932
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6933</div>
6934
6935<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6936<h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6937 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6938</h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6939
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6940<div>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6941
6942<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6943<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6944 floating point or vector of floating point type. Not all targets support all
6945 types however.</p>
6946
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6947<pre>
6948 declare float @llvm.cos.f32(float %Val)
6949 declare double @llvm.cos.f64(double %Val)
6950 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6951 declare fp128 @llvm.cos.f128(fp128 %Val)
6952 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6953</pre>
6954
6955<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6956<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6957
6958<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6959<p>The argument and return value are floating point numbers of the same
6960 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6961
6962<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6963<p>This function returns the cosine of the specified operand, returning the same
6964 values as the libm <tt>cos</tt> functions would, and handles error conditions
6965 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6966
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6967</div>
6968
6969<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6970<h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6971 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6972</h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6973
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6974<div>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6975
6976<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6977<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6978 floating point or vector of floating point type. Not all targets support all
6979 types however.</p>
6980
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6981<pre>
6982 declare float @llvm.pow.f32(float %Val, float %Power)
6983 declare double @llvm.pow.f64(double %Val, double %Power)
6984 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6985 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6986 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6987</pre>
6988
6989<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6990<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6991 specified (positive or negative) power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6992
6993<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6994<p>The second argument is a floating point power, and the first is a value to
6995 raise to that power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6996
6997<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6998<p>This function returns the first value raised to the second power, returning
6999 the same values as the libm <tt>pow</tt> functions would, and handles error
7000 conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7001
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7002</div>
7003
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7004</div>
7005
Dan Gohman911fa902011-05-23 21:13:03 +0000[diff] [blame]7006<!-- _______________________________________________________________________ -->
7007<h4>
7008 <a name="int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a>
7009</h4>
7010
7011<div>
7012
7013<h5>Syntax:</h5>
7014<p>This is an overloaded intrinsic. You can use <tt>llvm.exp</tt> on any
7015 floating point or vector of floating point type. Not all targets support all
7016 types however.</p>
7017
7018<pre>
7019 declare float @llvm.exp.f32(float %Val)
7020 declare double @llvm.exp.f64(double %Val)
7021 declare x86_fp80 @llvm.exp.f80(x86_fp80 %Val)
7022 declare fp128 @llvm.exp.f128(fp128 %Val)
7023 declare ppc_fp128 @llvm.exp.ppcf128(ppc_fp128 %Val)
7024</pre>
7025
7026<h5>Overview:</h5>
7027<p>The '<tt>llvm.exp.*</tt>' intrinsics perform the exp function.</p>
7028
7029<h5>Arguments:</h5>
7030<p>The argument and return value are floating point numbers of the same
7031 type.</p>
7032
7033<h5>Semantics:</h5>
7034<p>This function returns the same values as the libm <tt>exp</tt> functions
7035 would, and handles error conditions in the same way.</p>
7036
7037</div>
7038
7039<!-- _______________________________________________________________________ -->
7040<h4>
7041 <a name="int_log">'<tt>llvm.log.*</tt>' Intrinsic</a>
7042</h4>
7043
7044<div>
7045
7046<h5>Syntax:</h5>
7047<p>This is an overloaded intrinsic. You can use <tt>llvm.log</tt> on any
7048 floating point or vector of floating point type. Not all targets support all
7049 types however.</p>
7050
7051<pre>
7052 declare float @llvm.log.f32(float %Val)
7053 declare double @llvm.log.f64(double %Val)
7054 declare x86_fp80 @llvm.log.f80(x86_fp80 %Val)
7055 declare fp128 @llvm.log.f128(fp128 %Val)
7056 declare ppc_fp128 @llvm.log.ppcf128(ppc_fp128 %Val)
7057</pre>
7058
7059<h5>Overview:</h5>
7060<p>The '<tt>llvm.log.*</tt>' intrinsics perform the log function.</p>
7061
7062<h5>Arguments:</h5>
7063<p>The argument and return value are floating point numbers of the same
7064 type.</p>
7065
7066<h5>Semantics:</h5>
7067<p>This function returns the same values as the libm <tt>log</tt> functions
7068 would, and handles error conditions in the same way.</p>
7069
Cameron Zwarichf03fa182011-07-08 21:39:21 +0000[diff] [blame]7070<h4>
7071 <a name="int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a>
7072</h4>
7073
7074<div>
7075
7076<h5>Syntax:</h5>
7077<p>This is an overloaded intrinsic. You can use <tt>llvm.fma</tt> on any
7078 floating point or vector of floating point type. Not all targets support all
7079 types however.</p>
7080
7081<pre>
7082 declare float @llvm.fma.f32(float %a, float %b, float %c)
7083 declare double @llvm.fma.f64(double %a, double %b, double %c)
7084 declare x86_fp80 @llvm.fma.f80(x86_fp80 %a, x86_fp80 %b, x86_fp80 %c)
7085 declare fp128 @llvm.fma.f128(fp128 %a, fp128 %b, fp128 %c)
7086 declare ppc_fp128 @llvm.fma.ppcf128(ppc_fp128 %a, ppc_fp128 %b, ppc_fp128 %c)
7087</pre>
7088
7089<h5>Overview:</h5>
Cameron Zwaricha32fd212011-07-08 22:13:55 +0000[diff] [blame]7090<p>The '<tt>llvm.fma.*</tt>' intrinsics perform the fused multiply-add
Cameron Zwarichf03fa182011-07-08 21:39:21 +0000[diff] [blame]7091 operation.</p>
7092
7093<h5>Arguments:</h5>
7094<p>The argument and return value are floating point numbers of the same
7095 type.</p>
7096
7097<h5>Semantics:</h5>
7098<p>This function returns the same values as the libm <tt>fma</tt> functions
7099 would.</p>
7100
Dan Gohman911fa902011-05-23 21:13:03 +0000[diff] [blame]7101</div>
7102
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7103<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7104<h3>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7105 <a name="int_manip">Bit Manipulation Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7106</h3>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7107
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7108<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7109
7110<p>LLVM provides intrinsics for a few important bit manipulation operations.
7111 These allow efficient code generation for some algorithms.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7112
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7113<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7114<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]7115 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7116</h4>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7117
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7118<div>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7119
7120<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]7121<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7122 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
7123
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7124<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7125 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
7126 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
7127 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7128</pre>
7129
7130<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7131<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
7132 values with an even number of bytes (positive multiple of 16 bits). These
7133 are useful for performing operations on data that is not in the target's
7134 native byte order.</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7135
7136<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7137<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
7138 and low byte of the input i16 swapped. Similarly,
7139 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
7140 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
7141 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
7142 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
7143 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
7144 more, respectively).</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7145
7146</div>
7147
7148<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7149<h4>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]7150 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7151</h4>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7152
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7153<div>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7154
7155<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]7156<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7157 width, or on any vector with integer elements. Not all targets support all
7158 bit widths or vector types, however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7159
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7160<pre>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7161 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7162 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]7163 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7164 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
7165 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7166 declare &lt;2 x i32&gt; @llvm.ctpop.v2i32(&lt;2 x i32&gt; &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7167</pre>
7168
7169<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7170<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
7171 in a value.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7172
7173<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7174<p>The only argument is the value to be counted. The argument may be of any
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7175 integer type, or a vector with integer elements.
7176 The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7177
7178<h5>Semantics:</h5>
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7179<p>The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable, or within each
7180 element of a vector.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7181
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7182</div>
7183
7184<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7185<h4>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]7186 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7187</h4>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7188
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7189<div>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7190
7191<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7192<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7193 integer bit width, or any vector whose elements are integers. Not all
7194 targets support all bit widths or vector types, however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7195
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7196<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7197 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
7198 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]7199 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7200 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
7201 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7202 declare &lt;2 x i32&gt; @llvm.ctlz.v2i32(&lt;2 x i32&gt; &lt;src;gt)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7203</pre>
7204
7205<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7206<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
7207 leading zeros in a variable.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7208
7209<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7210<p>The only argument is the value to be counted. The argument may be of any
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7211 integer type, or any vector type with integer element type.
7212 The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7213
7214<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7215<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7216 zeros in a variable, or within each element of the vector if the operation
7217 is of vector type. If the src == 0 then the result is the size in bits of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7218 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7219
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7220</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]7221
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7222<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7223<h4>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]7224 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7225</h4>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7226
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7227<div>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7228
7229<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7230<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7231 integer bit width, or any vector of integer elements. Not all targets
7232 support all bit widths or vector types, however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7233
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7234<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7235 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
7236 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]7237 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7238 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
7239 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7240 declase &lt;2 x i32&gt; @llvm.cttz.v2i32(&lt;2 x i32&gt; &lt;src&gt;)
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7241</pre>
7242
7243<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7244<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
7245 trailing zeros.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7246
7247<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7248<p>The only argument is the value to be counted. The argument may be of any
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7249 integer type, or a vectory with integer element type.. The return type
7250 must match the argument type.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7251
7252<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7253<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7254 zeros in a variable, or within each element of a vector.
7255 If the src == 0 then the result is the size in bits of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7256 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7257
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7258</div>
7259
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7260</div>
7261
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]7262<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7263<h3>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]7264 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7265</h3>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]7266
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7267<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7268
7269<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]7270
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7271<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7272<h4>
7273 <a name="int_sadd_overflow">
7274 '<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics
7275 </a>
7276</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7277
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7278<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7279
7280<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7281<p>This is an overloaded intrinsic. You can use <tt>llvm.sadd.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7282 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7283
7284<pre>
7285 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
7286 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7287 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
7288</pre>
7289
7290<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7291<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7292 a signed addition of the two arguments, and indicate whether an overflow
7293 occurred during the signed summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7294
7295<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7296<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7297 be of integer types of any bit width, but they must have the same bit
7298 width. The second element of the result structure must be of
7299 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7300 undergo signed addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7301
7302<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7303<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7304 a signed addition of the two variables. They return a structure &mdash; the
7305 first element of which is the signed summation, and the second element of
7306 which is a bit specifying if the signed summation resulted in an
7307 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7308
7309<h5>Examples:</h5>
7310<pre>
7311 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7312 %sum = extractvalue {i32, i1} %res, 0
7313 %obit = extractvalue {i32, i1} %res, 1
7314 br i1 %obit, label %overflow, label %normal
7315</pre>
7316
7317</div>
7318
7319<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7320<h4>
7321 <a name="int_uadd_overflow">
7322 '<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics
7323 </a>
7324</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7325
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7326<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7327
7328<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7329<p>This is an overloaded intrinsic. You can use <tt>llvm.uadd.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7330 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7331
7332<pre>
7333 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
7334 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7335 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
7336</pre>
7337
7338<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7339<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7340 an unsigned addition of the two arguments, and indicate whether a carry
7341 occurred during the unsigned summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7342
7343<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7344<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7345 be of integer types of any bit width, but they must have the same bit
7346 width. The second element of the result structure must be of
7347 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7348 undergo unsigned addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7349
7350<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7351<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7352 an unsigned addition of the two arguments. They return a structure &mdash;
7353 the first element of which is the sum, and the second element of which is a
7354 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7355
7356<h5>Examples:</h5>
7357<pre>
7358 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7359 %sum = extractvalue {i32, i1} %res, 0
7360 %obit = extractvalue {i32, i1} %res, 1
7361 br i1 %obit, label %carry, label %normal
7362</pre>
7363
7364</div>
7365
7366<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7367<h4>
7368 <a name="int_ssub_overflow">
7369 '<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics
7370 </a>
7371</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7372
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7373<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7374
7375<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7376<p>This is an overloaded intrinsic. You can use <tt>llvm.ssub.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7377 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7378
7379<pre>
7380 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
7381 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7382 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
7383</pre>
7384
7385<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7386<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7387 a signed subtraction of the two arguments, and indicate whether an overflow
7388 occurred during the signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7389
7390<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7391<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7392 be of integer types of any bit width, but they must have the same bit
7393 width. The second element of the result structure must be of
7394 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7395 undergo signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7396
7397<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7398<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7399 a signed subtraction of the two arguments. They return a structure &mdash;
7400 the first element of which is the subtraction, and the second element of
7401 which is a bit specifying if the signed subtraction resulted in an
7402 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7403
7404<h5>Examples:</h5>
7405<pre>
7406 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7407 %sum = extractvalue {i32, i1} %res, 0
7408 %obit = extractvalue {i32, i1} %res, 1
7409 br i1 %obit, label %overflow, label %normal
7410</pre>
7411
7412</div>
7413
7414<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7415<h4>
7416 <a name="int_usub_overflow">
7417 '<tt>llvm.usub.with.overflow.*</tt>' Intrinsics
7418 </a>
7419</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7420
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7421<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7422
7423<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7424<p>This is an overloaded intrinsic. You can use <tt>llvm.usub.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7425 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7426
7427<pre>
7428 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
7429 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7430 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
7431</pre>
7432
7433<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7434<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7435 an unsigned subtraction of the two arguments, and indicate whether an
7436 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7437
7438<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7439<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7440 be of integer types of any bit width, but they must have the same bit
7441 width. The second element of the result structure must be of
7442 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7443 undergo unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7444
7445<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7446<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7447 an unsigned subtraction of the two arguments. They return a structure &mdash;
7448 the first element of which is the subtraction, and the second element of
7449 which is a bit specifying if the unsigned subtraction resulted in an
7450 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7451
7452<h5>Examples:</h5>
7453<pre>
7454 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7455 %sum = extractvalue {i32, i1} %res, 0
7456 %obit = extractvalue {i32, i1} %res, 1
7457 br i1 %obit, label %overflow, label %normal
7458</pre>
7459
7460</div>
7461
7462<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7463<h4>
7464 <a name="int_smul_overflow">
7465 '<tt>llvm.smul.with.overflow.*</tt>' Intrinsics
7466 </a>
7467</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7468
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7469<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7470
7471<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7472<p>This is an overloaded intrinsic. You can use <tt>llvm.smul.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7473 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7474
7475<pre>
7476 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
7477 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7478 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
7479</pre>
7480
7481<h5>Overview:</h5>
7482
7483<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7484 a signed multiplication of the two arguments, and indicate whether an
7485 overflow occurred during the signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7486
7487<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7488<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7489 be of integer types of any bit width, but they must have the same bit
7490 width. The second element of the result structure must be of
7491 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7492 undergo signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7493
7494<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7495<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7496 a signed multiplication of the two arguments. They return a structure &mdash;
7497 the first element of which is the multiplication, and the second element of
7498 which is a bit specifying if the signed multiplication resulted in an
7499 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7500
7501<h5>Examples:</h5>
7502<pre>
7503 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7504 %sum = extractvalue {i32, i1} %res, 0
7505 %obit = extractvalue {i32, i1} %res, 1
7506 br i1 %obit, label %overflow, label %normal
7507</pre>
7508
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]7509</div>
7510
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7511<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7512<h4>
7513 <a name="int_umul_overflow">
7514 '<tt>llvm.umul.with.overflow.*</tt>' Intrinsics
7515 </a>
7516</h4>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7517
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7518<div>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7519
7520<h5>Syntax:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7521<p>This is an overloaded intrinsic. You can use <tt>llvm.umul.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7522 on any integer bit width.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7523
7524<pre>
7525 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
7526 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
7527 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
7528</pre>
7529
7530<h5>Overview:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7531<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7532 a unsigned multiplication of the two arguments, and indicate whether an
7533 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7534
7535<h5>Arguments:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7536<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7537 be of integer types of any bit width, but they must have the same bit
7538 width. The second element of the result structure must be of
7539 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7540 undergo unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7541
7542<h5>Semantics:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7543<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7544 an unsigned multiplication of the two arguments. They return a structure
7545 &mdash; the first element of which is the multiplication, and the second
7546 element of which is a bit specifying if the unsigned multiplication resulted
7547 in an overflow.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7548
7549<h5>Examples:</h5>
7550<pre>
7551 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
7552 %sum = extractvalue {i32, i1} %res, 0
7553 %obit = extractvalue {i32, i1} %res, 1
7554 br i1 %obit, label %overflow, label %normal
7555</pre>
7556
7557</div>
7558
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7559</div>
7560
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]7561<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7562<h3>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7563 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7564</h3>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7565
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7566<div>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7567
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]7568<p>Half precision floating point is a storage-only format. This means that it is
7569 a dense encoding (in memory) but does not support computation in the
7570 format.</p>
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]7571
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]7572<p>This means that code must first load the half-precision floating point
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]7573 value as an i16, then convert it to float with <a
7574 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
7575 Computation can then be performed on the float value (including extending to
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]7576 double etc). To store the value back to memory, it is first converted to
7577 float if needed, then converted to i16 with
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]7578 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
7579 storing as an i16 value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7580
7581<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7582<h4>
7583 <a name="int_convert_to_fp16">
7584 '<tt>llvm.convert.to.fp16</tt>' Intrinsic
7585 </a>
7586</h4>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7587
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7588<div>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7589
7590<h5>Syntax:</h5>
7591<pre>
7592 declare i16 @llvm.convert.to.fp16(f32 %a)
7593</pre>
7594
7595<h5>Overview:</h5>
7596<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
7597 a conversion from single precision floating point format to half precision
7598 floating point format.</p>
7599
7600<h5>Arguments:</h5>
7601<p>The intrinsic function contains single argument - the value to be
7602 converted.</p>
7603
7604<h5>Semantics:</h5>
7605<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
7606 a conversion from single precision floating point format to half precision
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]7607 floating point format. The return value is an <tt>i16</tt> which
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]7608 contains the converted number.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7609
7610<h5>Examples:</h5>
7611<pre>
7612 %res = call i16 @llvm.convert.to.fp16(f32 %a)
7613 store i16 %res, i16* @x, align 2
7614</pre>
7615
7616</div>
7617
7618<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7619<h4>
7620 <a name="int_convert_from_fp16">
7621 '<tt>llvm.convert.from.fp16</tt>' Intrinsic
7622 </a>
7623</h4>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7624
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7625<div>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7626
7627<h5>Syntax:</h5>
7628<pre>
7629 declare f32 @llvm.convert.from.fp16(i16 %a)
7630</pre>
7631
7632<h5>Overview:</h5>
7633<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
7634 a conversion from half precision floating point format to single precision
7635 floating point format.</p>
7636
7637<h5>Arguments:</h5>
7638<p>The intrinsic function contains single argument - the value to be
7639 converted.</p>
7640
7641<h5>Semantics:</h5>
7642<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]7643 conversion from half single precision floating point format to single
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]7644 precision floating point format. The input half-float value is represented by
7645 an <tt>i16</tt> value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7646
7647<h5>Examples:</h5>
7648<pre>
7649 %a = load i16* @x, align 2
7650 %res = call f32 @llvm.convert.from.fp16(i16 %a)
7651</pre>
7652
7653</div>
7654
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7655</div>
7656
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7657<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7658<h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]7659 <a name="int_debugger">Debugger Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7660</h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]7661
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7662<div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]7663
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7664<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
7665 prefix), are described in
7666 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
7667 Level Debugging</a> document.</p>
7668
7669</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]7670
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7671<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7672<h3>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7673 <a name="int_eh">Exception Handling Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7674</h3>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7675
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7676<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7677
7678<p>The LLVM exception handling intrinsics (which all start with
7679 <tt>llvm.eh.</tt> prefix), are described in
7680 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
7681 Handling</a> document.</p>
7682
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7683</div>
7684
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7685<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7686<h3>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]7687 <a name="int_trampoline">Trampoline Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7688</h3>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7689
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7690<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7691
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]7692<p>These intrinsics make it possible to excise one parameter, marked with
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]7693 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
7694 The result is a callable
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7695 function pointer lacking the nest parameter - the caller does not need to
7696 provide a value for it. Instead, the value to use is stored in advance in a
7697 "trampoline", a block of memory usually allocated on the stack, which also
7698 contains code to splice the nest value into the argument list. This is used
7699 to implement the GCC nested function address extension.</p>
7700
7701<p>For example, if the function is
7702 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
7703 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
7704 follows:</p>
7705
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]7706<pre class="doc_code">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]7707 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
7708 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]7709 call i8* @llvm.init.trampoline(i8* %tramp1, i8* bitcast (i32 (i8*, i32, i32)* @f to i8*), i8* %nval)
7710 %p = call i8* @llvm.adjust.trampoline(i8* %tramp1)
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]7711 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7712</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7713
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7714<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
7715 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7716
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7717<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7718<h4>
7719 <a name="int_it">
7720 '<tt>llvm.init.trampoline</tt>' Intrinsic
7721 </a>
7722</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7723
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7724<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7725
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7726<h5>Syntax:</h5>
7727<pre>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]7728 declare void @llvm.init.trampoline(i8* &lt;tramp&gt;, i8* &lt;func&gt;, i8* &lt;nval&gt;)
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7729</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7730
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7731<h5>Overview:</h5>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]7732<p>This fills the memory pointed to by <tt>tramp</tt> with executable code,
7733 turning it into a trampoline.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7734
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7735<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7736<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
7737 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
7738 sufficiently aligned block of memory; this memory is written to by the
7739 intrinsic. Note that the size and the alignment are target-specific - LLVM
7740 currently provides no portable way of determining them, so a front-end that
7741 generates this intrinsic needs to have some target-specific knowledge.
7742 The <tt>func</tt> argument must hold a function bitcast to
7743 an <tt>i8*</tt>.</p>
7744
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7745<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7746<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]7747 dependent code, turning it into a function. Then <tt>tramp</tt> needs to be
7748 passed to <a href="#int_at">llvm.adjust.trampoline</a> to get a pointer
7749 which can be <a href="#int_trampoline">bitcast (to a new function) and
7750 called</a>. The new function's signature is the same as that of
7751 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
7752 removed. At most one such <tt>nest</tt> argument is allowed, and it must be of
7753 pointer type. Calling the new function is equivalent to calling <tt>func</tt>
7754 with the same argument list, but with <tt>nval</tt> used for the missing
7755 <tt>nest</tt> argument. If, after calling <tt>llvm.init.trampoline</tt>, the
7756 memory pointed to by <tt>tramp</tt> is modified, then the effect of any later call
7757 to the returned function pointer is undefined.</p>
7758</div>
7759
7760<!-- _______________________________________________________________________ -->
7761<h4>
7762 <a name="int_at">
7763 '<tt>llvm.adjust.trampoline</tt>' Intrinsic
7764 </a>
7765</h4>
7766
7767<div>
7768
7769<h5>Syntax:</h5>
7770<pre>
7771 declare i8* @llvm.adjust.trampoline(i8* &lt;tramp&gt;)
7772</pre>
7773
7774<h5>Overview:</h5>
7775<p>This performs any required machine-specific adjustment to the address of a
7776 trampoline (passed as <tt>tramp</tt>).</p>
7777
7778<h5>Arguments:</h5>
7779<p><tt>tramp</tt> must point to a block of memory which already has trampoline code
7780 filled in by a previous call to <a href="#int_it"><tt>llvm.init.trampoline</tt>
7781 </a>.</p>
7782
7783<h5>Semantics:</h5>
7784<p>On some architectures the address of the code to be executed needs to be
7785 different to the address where the trampoline is actually stored. This
7786 intrinsic returns the executable address corresponding to <tt>tramp</tt>
7787 after performing the required machine specific adjustments.
7788 The pointer returned can then be <a href="#int_trampoline"> bitcast and
7789 executed</a>.
7790</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7791
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7792</div>
7793
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7794</div>
7795
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7796<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7797<h3>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7798 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7799</h3>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7800
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7801<div>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7802
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7803<p>These intrinsic functions expand the "universal IR" of LLVM to represent
7804 hardware constructs for atomic operations and memory synchronization. This
7805 provides an interface to the hardware, not an interface to the programmer. It
7806 is aimed at a low enough level to allow any programming models or APIs
7807 (Application Programming Interfaces) which need atomic behaviors to map
7808 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
7809 hardware provides a "universal IR" for source languages, it also provides a
7810 starting point for developing a "universal" atomic operation and
7811 synchronization IR.</p>
7812
7813<p>These do <em>not</em> form an API such as high-level threading libraries,
7814 software transaction memory systems, atomic primitives, and intrinsic
7815 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
7816 application libraries. The hardware interface provided by LLVM should allow
7817 a clean implementation of all of these APIs and parallel programming models.
7818 No one model or paradigm should be selected above others unless the hardware
7819 itself ubiquitously does so.</p>
7820
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7821<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7822<h4>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7823 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7824</h4>
7825
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7826<div>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7827<h5>Syntax:</h5>
7828<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7829 declare void @llvm.memory.barrier(i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;, i1 &lt;device&gt;)
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7830</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7831
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7832<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7833<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
7834 specific pairs of memory access types.</p>
7835
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7836<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7837<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
7838 The first four arguments enables a specific barrier as listed below. The
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]7839 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7840 memory.</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7841
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7842<ul>
7843 <li><tt>ll</tt>: load-load barrier</li>
7844 <li><tt>ls</tt>: load-store barrier</li>
7845 <li><tt>sl</tt>: store-load barrier</li>
7846 <li><tt>ss</tt>: store-store barrier</li>
7847 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
7848</ul>
7849
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7850<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7851<p>This intrinsic causes the system to enforce some ordering constraints upon
7852 the loads and stores of the program. This barrier does not
7853 indicate <em>when</em> any events will occur, it only enforces
7854 an <em>order</em> in which they occur. For any of the specified pairs of load
7855 and store operations (f.ex. load-load, or store-load), all of the first
7856 operations preceding the barrier will complete before any of the second
7857 operations succeeding the barrier begin. Specifically the semantics for each
7858 pairing is as follows:</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7859
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7860<ul>
7861 <li><tt>ll</tt>: All loads before the barrier must complete before any load
7862 after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7863 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7864 store after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7865 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7866 store after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7867 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7868 load after the barrier begins.</li>
7869</ul>
7870
7871<p>These semantics are applied with a logical "and" behavior when more than one
7872 is enabled in a single memory barrier intrinsic.</p>
7873
7874<p>Backends may implement stronger barriers than those requested when they do
7875 not support as fine grained a barrier as requested. Some architectures do
7876 not need all types of barriers and on such architectures, these become
7877 noops.</p>
7878
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7879<h5>Example:</h5>
7880<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7881%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7882%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7883 store i32 4, %ptr
7884
7885%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
Evan Cheng0ac49c62011-06-29 17:14:00 +0000[diff] [blame]7886 call void @llvm.memory.barrier(i1 false, i1 true, i1 false, i1 false, i1 true)
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7887 <i>; guarantee the above finishes</i>
7888 store i32 8, %ptr <i>; before this begins</i>
7889</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7890
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7891</div>
7892
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7893<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7894<h4>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7895 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7896</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7897
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7898<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7899
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7900<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7901<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
7902 any integer bit width and for different address spaces. Not all targets
7903 support all bit widths however.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7904
7905<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7906 declare i8 @llvm.atomic.cmp.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt;)
7907 declare i16 @llvm.atomic.cmp.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt;)
7908 declare i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt;)
7909 declare i64 @llvm.atomic.cmp.swap.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;cmp&gt;, i64 &lt;val&gt;)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7910</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7911
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7912<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7913<p>This loads a value in memory and compares it to a given value. If they are
7914 equal, it stores a new value into the memory.</p>
7915
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7916<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7917<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7918 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7919 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7920 this integer type. While any bit width integer may be used, targets may only
7921 lower representations they support in hardware.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7922
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7923<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7924<p>This entire intrinsic must be executed atomically. It first loads the value
7925 in memory pointed to by <tt>ptr</tt> and compares it with the
7926 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7927 memory. The loaded value is yielded in all cases. This provides the
7928 equivalent of an atomic compare-and-swap operation within the SSA
7929 framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7930
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7931<h5>Examples:</h5>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7932<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7933%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7934%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7935 store i32 4, %ptr
7936
7937%val1 = add i32 4, 4
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7938%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 4, %val1)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7939 <i>; yields {i32}:result1 = 4</i>
7940%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7941%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7942
7943%val2 = add i32 1, 1
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7944%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 5, %val2)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7945 <i>; yields {i32}:result2 = 8</i>
7946%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7947
7948%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7949</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7950
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7951</div>
7952
7953<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7954<h4>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7955 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7956</h4>
7957
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7958<div>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7959<h5>Syntax:</h5>
7960
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7961<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7962 integer bit width. Not all targets support all bit widths however.</p>
7963
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7964<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7965 declare i8 @llvm.atomic.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;val&gt;)
7966 declare i16 @llvm.atomic.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;val&gt;)
7967 declare i32 @llvm.atomic.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;val&gt;)
7968 declare i64 @llvm.atomic.swap.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;val&gt;)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7969</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7970
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7971<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7972<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7973 the value from memory. It then stores the value in <tt>val</tt> in the memory
7974 at <tt>ptr</tt>.</p>
7975
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7976<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7977<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7978 the <tt>val</tt> argument and the result must be integers of the same bit
7979 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7980 integer type. The targets may only lower integer representations they
7981 support.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7982
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7983<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7984<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
7985 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
7986 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7987
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7988<h5>Examples:</h5>
7989<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7990%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7991%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7992 store i32 4, %ptr
7993
7994%val1 = add i32 4, 4
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7995%result1 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val1)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7996 <i>; yields {i32}:result1 = 4</i>
7997%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7998%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7999
8000%val2 = add i32 1, 1
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8001%result2 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val2)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8002 <i>; yields {i32}:result2 = 8</i>
8003
8004%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
8005%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
8006</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8007
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8008</div>
8009
8010<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8011<h4>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8012 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8013</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8014
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8015<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8016
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8017<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8018<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
8019 any integer bit width. Not all targets support all bit widths however.</p>
8020
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8021<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8022 declare i8 @llvm.atomic.load.add.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
8023 declare i16 @llvm.atomic.load.add.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
8024 declare i32 @llvm.atomic.load.add.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
8025 declare i64 @llvm.atomic.load.add.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8026</pre>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8027
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8028<h5>Overview:</h5>
8029<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
8030 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
8031
8032<h5>Arguments:</h5>
8033<p>The intrinsic takes two arguments, the first a pointer to an integer value
8034 and the second an integer value. The result is also an integer value. These
8035 integer types can have any bit width, but they must all have the same bit
8036 width. The targets may only lower integer representations they support.</p>
8037
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8038<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8039<p>This intrinsic does a series of operations atomically. It first loads the
8040 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
8041 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8042
8043<h5>Examples:</h5>
8044<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]8045%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
8046%ptr = bitcast i8* %mallocP to i32*
8047 store i32 4, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8048%result1 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 4)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8049 <i>; yields {i32}:result1 = 4</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8050%result2 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 2)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8051 <i>; yields {i32}:result2 = 8</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8052%result3 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 5)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8053 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8054%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8055</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8056
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]8057</div>
8058
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8059<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8060<h4>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8061 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8062</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8063
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8064<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8065
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8066<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8067<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
8068 any integer bit width and for different address spaces. Not all targets
8069 support all bit widths however.</p>
8070
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8071<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8072 declare i8 @llvm.atomic.load.sub.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
8073 declare i16 @llvm.atomic.load.sub.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
8074 declare i32 @llvm.atomic.load.sub.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
8075 declare i64 @llvm.atomic.load.sub.i64.p0i32(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8076</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8077
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8078<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]8079<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8080 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
8081
8082<h5>Arguments:</h5>
8083<p>The intrinsic takes two arguments, the first a pointer to an integer value
8084 and the second an integer value. The result is also an integer value. These
8085 integer types can have any bit width, but they must all have the same bit
8086 width. The targets may only lower integer representations they support.</p>
8087
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8088<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8089<p>This intrinsic does a series of operations atomically. It first loads the
8090 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
8091 result to <tt>ptr</tt>. It yields the original value stored
8092 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8093
8094<h5>Examples:</h5>
8095<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]8096%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
8097%ptr = bitcast i8* %mallocP to i32*
8098 store i32 8, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8099%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 4)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8100 <i>; yields {i32}:result1 = 8</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8101%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 2)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8102 <i>; yields {i32}:result2 = 4</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8103%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 5)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8104 <i>; yields {i32}:result3 = 2</i>
8105%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
8106</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8107
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8108</div>
8109
8110<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8111<h4>
8112 <a name="int_atomic_load_and">
8113 '<tt>llvm.atomic.load.and.*</tt>' Intrinsic
8114 </a>
8115 <br>
8116 <a name="int_atomic_load_nand">
8117 '<tt>llvm.atomic.load.nand.*</tt>' Intrinsic
8118 </a>
8119 <br>
8120 <a name="int_atomic_load_or">
8121 '<tt>llvm.atomic.load.or.*</tt>' Intrinsic
8122 </a>
8123 <br>
8124 <a name="int_atomic_load_xor">
8125 '<tt>llvm.atomic.load.xor.*</tt>' Intrinsic
8126 </a>
8127</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8128
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8129<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8130
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8131<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8132<p>These are overloaded intrinsics. You can
8133 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
8134 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
8135 bit width and for different address spaces. Not all targets support all bit
8136 widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8137
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8138<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8139 declare i8 @llvm.atomic.load.and.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
8140 declare i16 @llvm.atomic.load.and.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
8141 declare i32 @llvm.atomic.load.and.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
8142 declare i64 @llvm.atomic.load.and.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8143</pre>
8144
8145<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8146 declare i8 @llvm.atomic.load.or.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
8147 declare i16 @llvm.atomic.load.or.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
8148 declare i32 @llvm.atomic.load.or.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
8149 declare i64 @llvm.atomic.load.or.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8150</pre>
8151
8152<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8153 declare i8 @llvm.atomic.load.nand.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
8154 declare i16 @llvm.atomic.load.nand.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
8155 declare i32 @llvm.atomic.load.nand.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
8156 declare i64 @llvm.atomic.load.nand.i64.p0i32(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8157</pre>
8158
8159<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8160 declare i8 @llvm.atomic.load.xor.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
8161 declare i16 @llvm.atomic.load.xor.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
8162 declare i32 @llvm.atomic.load.xor.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
8163 declare i64 @llvm.atomic.load.xor.i64.p0i32(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8164</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8165
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8166<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8167<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
8168 the value stored in memory at <tt>ptr</tt>. It yields the original value
8169 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8170
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8171<h5>Arguments:</h5>
8172<p>These intrinsics take two arguments, the first a pointer to an integer value
8173 and the second an integer value. The result is also an integer value. These
8174 integer types can have any bit width, but they must all have the same bit
8175 width. The targets may only lower integer representations they support.</p>
8176
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8177<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8178<p>These intrinsics does a series of operations atomically. They first load the
8179 value stored at <tt>ptr</tt>. They then do the bitwise
8180 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
8181 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8182
8183<h5>Examples:</h5>
8184<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]8185%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
8186%ptr = bitcast i8* %mallocP to i32*
8187 store i32 0x0F0F, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8188%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8189 <i>; yields {i32}:result0 = 0x0F0F</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8190%result1 = call i32 @llvm.atomic.load.and.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8191 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8192%result2 = call i32 @llvm.atomic.load.or.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8193 <i>; yields {i32}:result2 = 0xF0</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8194%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8195 <i>; yields {i32}:result3 = FF</i>
8196%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
8197</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8198
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8199</div>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8200
8201<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8202<h4>
8203 <a name="int_atomic_load_max">
8204 '<tt>llvm.atomic.load.max.*</tt>' Intrinsic
8205 </a>
8206 <br>
8207 <a name="int_atomic_load_min">
8208 '<tt>llvm.atomic.load.min.*</tt>' Intrinsic
8209 </a>
8210 <br>
8211 <a name="int_atomic_load_umax">
8212 '<tt>llvm.atomic.load.umax.*</tt>' Intrinsic
8213 </a>
8214 <br>
8215 <a name="int_atomic_load_umin">
8216 '<tt>llvm.atomic.load.umin.*</tt>' Intrinsic
8217 </a>
8218</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8219
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8220<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8221
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8222<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8223<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
8224 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
8225 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
8226 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8227
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8228<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8229 declare i8 @llvm.atomic.load.max.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
8230 declare i16 @llvm.atomic.load.max.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
8231 declare i32 @llvm.atomic.load.max.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
8232 declare i64 @llvm.atomic.load.max.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8233</pre>
8234
8235<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8236 declare i8 @llvm.atomic.load.min.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
8237 declare i16 @llvm.atomic.load.min.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
8238 declare i32 @llvm.atomic.load.min.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
8239 declare i64 @llvm.atomic.load.min.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8240</pre>
8241
8242<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8243 declare i8 @llvm.atomic.load.umax.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
8244 declare i16 @llvm.atomic.load.umax.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
8245 declare i32 @llvm.atomic.load.umax.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
8246 declare i64 @llvm.atomic.load.umax.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8247</pre>
8248
8249<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8250 declare i8 @llvm.atomic.load.umin.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
8251 declare i16 @llvm.atomic.load.umin.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
8252 declare i32 @llvm.atomic.load.umin.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
8253 declare i64 @llvm.atomic.load.umin.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8254</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8255
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8256<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]8257<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8258 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
8259 original value at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8260
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8261<h5>Arguments:</h5>
8262<p>These intrinsics take two arguments, the first a pointer to an integer value
8263 and the second an integer value. The result is also an integer value. These
8264 integer types can have any bit width, but they must all have the same bit
8265 width. The targets may only lower integer representations they support.</p>
8266
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8267<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8268<p>These intrinsics does a series of operations atomically. They first load the
8269 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
8270 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
8271 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8272
8273<h5>Examples:</h5>
8274<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]8275%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
8276%ptr = bitcast i8* %mallocP to i32*
8277 store i32 7, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8278%result0 = call i32 @llvm.atomic.load.min.i32.p0i32(i32* %ptr, i32 -2)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8279 <i>; yields {i32}:result0 = 7</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8280%result1 = call i32 @llvm.atomic.load.max.i32.p0i32(i32* %ptr, i32 8)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8281 <i>; yields {i32}:result1 = -2</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8282%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32(i32* %ptr, i32 10)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8283 <i>; yields {i32}:result2 = 8</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8284%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32(i32* %ptr, i32 30)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8285 <i>; yields {i32}:result3 = 8</i>
8286%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
8287</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8288
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]8289</div>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]8290
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8291</div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8292
8293<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8294<h3>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8295 <a name="int_memorymarkers">Memory Use Markers</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8296</h3>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8297
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8298<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8299
8300<p>This class of intrinsics exists to information about the lifetime of memory
8301 objects and ranges where variables are immutable.</p>
8302
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8303<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8304<h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8305 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8306</h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8307
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8308<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8309
8310<h5>Syntax:</h5>
8311<pre>
8312 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8313</pre>
8314
8315<h5>Overview:</h5>
8316<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
8317 object's lifetime.</p>
8318
8319<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]8320<p>The first argument is a constant integer representing the size of the
8321 object, or -1 if it is variable sized. The second argument is a pointer to
8322 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8323
8324<h5>Semantics:</h5>
8325<p>This intrinsic indicates that before this point in the code, the value of the
8326 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
Nick Lewyckyd20fd592009-10-27 16:56:58 +0000[diff] [blame]8327 never be used and has an undefined value. A load from the pointer that
8328 precedes this intrinsic can be replaced with
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8329 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
8330
8331</div>
8332
8333<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8334<h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8335 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8336</h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8337
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8338<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8339
8340<h5>Syntax:</h5>
8341<pre>
8342 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8343</pre>
8344
8345<h5>Overview:</h5>
8346<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
8347 object's lifetime.</p>
8348
8349<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]8350<p>The first argument is a constant integer representing the size of the
8351 object, or -1 if it is variable sized. The second argument is a pointer to
8352 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8353
8354<h5>Semantics:</h5>
8355<p>This intrinsic indicates that after this point in the code, the value of the
8356 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
8357 never be used and has an undefined value. Any stores into the memory object
8358 following this intrinsic may be removed as dead.
8359
8360</div>
8361
8362<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8363<h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8364 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8365</h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8366
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8367<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8368
8369<h5>Syntax:</h5>
8370<pre>
Nick Lewycky2965d3e2010-11-30 04:13:41 +0000[diff] [blame]8371 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8372</pre>
8373
8374<h5>Overview:</h5>
8375<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
8376 a memory object will not change.</p>
8377
8378<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]8379<p>The first argument is a constant integer representing the size of the
8380 object, or -1 if it is variable sized. The second argument is a pointer to
8381 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8382
8383<h5>Semantics:</h5>
8384<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
8385 the return value, the referenced memory location is constant and
8386 unchanging.</p>
8387
8388</div>
8389
8390<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8391<h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8392 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8393</h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8394
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8395<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8396
8397<h5>Syntax:</h5>
8398<pre>
8399 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8400</pre>
8401
8402<h5>Overview:</h5>
8403<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
8404 a memory object are mutable.</p>
8405
8406<h5>Arguments:</h5>
8407<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]8408 The second argument is a constant integer representing the size of the
8409 object, or -1 if it is variable sized and the third argument is a pointer
8410 to the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8411
8412<h5>Semantics:</h5>
8413<p>This intrinsic indicates that the memory is mutable again.</p>
8414
8415</div>
8416
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8417</div>
8418
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]8419<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8420<h3>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8421 <a name="int_general">General Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8422</h3>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8423
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8424<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8425
8426<p>This class of intrinsics is designed to be generic and has no specific
8427 purpose.</p>
8428
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8429<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8430<h4>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8431 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8432</h4>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8433
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8434<div>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8435
8436<h5>Syntax:</h5>
8437<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8438 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8439</pre>
8440
8441<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8442<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8443
8444<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8445<p>The first argument is a pointer to a value, the second is a pointer to a
8446 global string, the third is a pointer to a global string which is the source
8447 file name, and the last argument is the line number.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8448
8449<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8450<p>This intrinsic allows annotation of local variables with arbitrary strings.
8451 This can be useful for special purpose optimizations that want to look for
John Criswellf0d536a2011-08-19 16:57:55 +0000[diff] [blame]8452 these annotations. These have no other defined use; they are ignored by code
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8453 generation and optimization.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8454
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8455</div>
8456
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8457<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8458<h4>
Tanya Lattner0186a652007-09-21 23:57:59 +0000[diff] [blame]8459 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8460</h4>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8461
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8462<div>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8463
8464<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8465<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
8466 any integer bit width.</p>
8467
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8468<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8469 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8470 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8471 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8472 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8473 declare i256 @llvm.annotation.i256(i256 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8474</pre>
8475
8476<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8477<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8478
8479<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8480<p>The first argument is an integer value (result of some expression), the
8481 second is a pointer to a global string, the third is a pointer to a global
8482 string which is the source file name, and the last argument is the line
8483 number. It returns the value of the first argument.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8484
8485<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8486<p>This intrinsic allows annotations to be put on arbitrary expressions with
8487 arbitrary strings. This can be useful for special purpose optimizations that
John Criswellf0d536a2011-08-19 16:57:55 +0000[diff] [blame]8488 want to look for these annotations. These have no other defined use; they
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8489 are ignored by code generation and optimization.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8490
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8491</div>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]8492
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8493<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8494<h4>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8495 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8496</h4>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8497
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8498<div>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8499
8500<h5>Syntax:</h5>
8501<pre>
8502 declare void @llvm.trap()
8503</pre>
8504
8505<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8506<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8507
8508<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8509<p>None.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8510
8511<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8512<p>This intrinsics is lowered to the target dependent trap instruction. If the
8513 target does not have a trap instruction, this intrinsic will be lowered to
8514 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8515
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8516</div>
8517
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8518<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8519<h4>
Misha Brukman50de2b22008-11-22 23:55:29 +0000[diff] [blame]8520 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8521</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8522
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8523<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8524
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8525<h5>Syntax:</h5>
8526<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8527 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8528</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8529
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8530<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8531<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
8532 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
8533 ensure that it is placed on the stack before local variables.</p>
8534
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8535<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8536<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
8537 arguments. The first argument is the value loaded from the stack
8538 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
8539 that has enough space to hold the value of the guard.</p>
8540
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8541<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8542<p>This intrinsic causes the prologue/epilogue inserter to force the position of
8543 the <tt>AllocaInst</tt> stack slot to be before local variables on the
8544 stack. This is to ensure that if a local variable on the stack is
8545 overwritten, it will destroy the value of the guard. When the function exits,
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8546 the guard on the stack is checked against the original guard. If they are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8547 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
8548 function.</p>
8549
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8550</div>
8551
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8552<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8553<h4>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8554 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8555</h4>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8556
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8557<div>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8558
8559<h5>Syntax:</h5>
8560<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8561 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
8562 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8563</pre>
8564
8565<h5>Overview:</h5>
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8566<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information to
8567 the optimizers to determine at compile time whether a) an operation (like
8568 memcpy) will overflow a buffer that corresponds to an object, or b) that a
8569 runtime check for overflow isn't necessary. An object in this context means
8570 an allocation of a specific class, structure, array, or other object.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8571
8572<h5>Arguments:</h5>
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8573<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]8574 argument is a pointer to or into the <tt>object</tt>. The second argument
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8575 is a boolean 0 or 1. This argument determines whether you want the
8576 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]8577 1, variables are not allowed.</p>
8578
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8579<h5>Semantics:</h5>
8580<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8581 representing the size of the object concerned, or <tt>i32/i64 -1 or 0</tt>,
8582 depending on the <tt>type</tt> argument, if the size cannot be determined at
8583 compile time.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8584
8585</div>
8586
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8587</div>
8588
8589</div>
8590
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]8591<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]8592<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]8593<address>
8594 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]8595 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]8596 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]8597 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]8598
8599 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
NAKAMURA Takumica46f5a2011-04-09 02:13:37 +0000[diff] [blame]8600 <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]8601 Last modified: $Date$
8602</address>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]8603
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]8604</body>
8605</html>